(!)Due to Microsoft's end of support for Internet Explorer 11 on 15/06/2022, this site does not support the recommended environment.

  • Penghentian penjualan kategori produk pneumatik Seri Ekonomi (E-series). Info Detail
    Notice of End of Sales for Economy Series Pneumatic Equipment Category. More information.

Solenoid Valves(Pressure Rating:-0.1 to 0.7)

Solenoid Valve is a vital electromechanical component for beginner engineers in factory automation, operates based on electromagnetism, where an electric current creates a magnetic field to control fluid or gas flow. With its user-friendly design and precise flow control, it is easy to integrate into various projects, making it ideal for beginners. Available in different types like 2-way, 3-way, and 4-way solenoid valves, each suited for specific applications, our product ensures versatility and efficiency. Its compact, durable construction allows for longevity and suitability in tight spaces and harsh industrial environments. From regulating water in irrigation and plumbing systems to controlling air and gas flow in pneumatic setups, the solenoid valve proves highly adaptable. Additionally, it emphasizes energy efficiency, requiring minimal consumption, contributing to cost-effective and eco-friendly automation solutions. Integrate our Solenoid Valve for reliable and efficient flow control, elevating the performance of your factory automation processes.
Days to Ship
  • All
  • Same day
  • 1 Day(s) or Less
  • 3 Day(s) or Less
  • 4 Day(s) or Less
  • 5 Day(s) or Less
  • 8 Day(s) or Less
  • 9 Day(s) or Less
  • 11 Day(s) or Less
  • 12 Day(s) or Less
  • 13 Day(s) or Less
  1. 1
Brand
Product Series
CAD
Days to Ship
Number of Ports
Application
Switching Type
Voltage
Number of Solenoids
Mounting Orientation
Pipe Port Type
Specifications
Status at Power Off
Plumbing Thread Nominal
Plumbing
Applicable Cylinder Dia.(Ø)
Type
Driving Type
Connecting Tube Diameter
Pressure Rating(MPa)
Seal Type
CV Value
Pilot Air Supply
  • On Sale Till 31/03/2025

5-Port Solenoid Valve Body Ported Single Unit SY5000 Series

  • On Sale Till 31/12/2024

5-Port Solenoid Valve Body Ported Single Unit SY7000 Series

  • On Sale Till 31/12/2024

5-Port Solenoid Valve, Base Mounted, Single Unit SY3000/5000/7000/9000 Series

  • On Sale Till 31/12/2024

5-Port Solenoid Valve Body Ported Single Unit SY3000 Series

    5-Port Solenoid Valve, Rubber Seal, SYJ7000 Series

    • On Sale Till 31/12/2024

    3-Port Solenoid Valve, Elastic Material Seal, Pilot / Poppet Type, Body Ported, Starter

    • On Sale Till 31/12/2024

    5-Port Solenoid Valve, Plug In, Metal Base SY3000/5000/7000 Series, Base Mounted Valve

      5-Port Solenoid Valve, Rubber Seal, SYJ5000 Series

      • On Sale Till 31/12/2024

      3-Port Solenoid Valve, Elastic Material Seal, Pilot / Poppet Type, Base Mounted, Starter

        3-Port Solenoid Valve, Pilot Type, Rubber Seal SYJ500 Series

          4-Port Solenoid Valve, SJ2000/3000 Series

            3-Port Solenoid Valve, Pilot Type, Rubber Seal SYJ700 Series

              3-Port Solenoid Valve, Pilot Type, Rubber Seal SYJ300 Series

                5-Port Solenoid Valve, SV1000/2000/3000/4000 Series

                  5-Port Solenoid Valve, Plug-In, SY3000/5000/7000 Series, Single Unit / Sub-Plate Type

                    ATEX Directive 5-Port Solenoid Valve 52-SY Series ATEX Category 2

                      3-Port Solenoid Valve, Body Ported / Base Mounted, Rubber Seal VZ500 Series

                        3-Port Solenoid Valve, Body Ported / Base Mounted, Elastic Body Seal, VZ300 Series

                          5-Port Solenoid Valve, Plug-In SY3000/SY5000/SY7000 Series

                          • On Sale Till 31/12/2024

                          5-Port Solenoid Valve, Plug-In Cassette Type, SZ3000 Series Valve

                            UL Standard Compliant 5-Port Solenoid Valve, Base Mounted, SY3000/5000/7000/9000

                              5-Port Solenoid Valve, Base Mounted, Clean, 10-SY3000/5000/7000/9000

                              • Economy

                              Vacuum Release Valve w/Restrictor SY3000, SY5000 (24 V DC)

                                3-Port Solenoid Valve, Elastic Material Seal, Pilot / Poppet Type, Body Ported, Rechargeable Battery Compatible

                                  3-Port Solenoid Valve, Elastic Seal, Pilot / Poppet Type, Base Mounted, Rechargeable Battery Compatible

                                    Intrinsically Safe Explosion-Proof Structure Certified (Japan) 5-Port Solenoid Valve, Base Mounted, 51-SY5000/7000/9000

                                      Individual wiring manifold, direct acting 3-port valve M3PA/B series, electromagnetic valve, unit

                                        Vacuum Release Valve With Throttle Valve SJ3A6 Series

                                          5-Port Solenoid Valve, Base Mounted, Single Unit, Rechargeable Battery Compatible, 25A-SY5000/7000 Series

                                          Brand

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          SMC

                                          CKD

                                          SMC

                                          SMC

                                          Product Series

                                          5-Port Solenoid Valve Body Ported Single Unit SY5000 Series

                                          5-Port Solenoid Valve Body Ported Single Unit SY7000 Series

                                          5-Port Solenoid Valve, Base Mounted, Single Unit SY3000/5000/7000/9000 Series

                                          5-Port Solenoid Valve Body Ported Single Unit SY3000 Series

                                          5-Port Solenoid Valve, Rubber Seal, SYJ7000 Series

                                          3-Port Solenoid Valve, Elastic Material Seal, Pilot / Poppet Type, Body Ported, Starter

                                          5-Port Solenoid Valve, Plug In, Metal Base SY3000/5000/7000 Series, Base Mounted Valve

                                          5-Port Solenoid Valve, Rubber Seal, SYJ5000 Series

                                          3-Port Solenoid Valve, Elastic Material Seal, Pilot / Poppet Type, Base Mounted, Starter

                                          3-Port Solenoid Valve, Pilot Type, Rubber Seal SYJ500 Series

                                          4-Port Solenoid Valve, SJ2000/3000 Series

                                          3-Port Solenoid Valve, Pilot Type, Rubber Seal SYJ700 Series

                                          3-Port Solenoid Valve, Pilot Type, Rubber Seal SYJ300 Series

                                          5-Port Solenoid Valve, SV1000/2000/3000/4000 Series

                                          5-Port Solenoid Valve, Plug-In, SY3000/5000/7000 Series, Single Unit / Sub-Plate Type

                                          ATEX Directive 5-Port Solenoid Valve 52-SY Series ATEX Category 2

                                          3-Port Solenoid Valve, Body Ported / Base Mounted, Rubber Seal VZ500 Series

                                          3-Port Solenoid Valve, Body Ported / Base Mounted, Elastic Body Seal, VZ300 Series

                                          5-Port Solenoid Valve, Plug-In SY3000/SY5000/SY7000 Series

                                          5-Port Solenoid Valve, Plug-In Cassette Type, SZ3000 Series Valve

                                          UL Standard Compliant 5-Port Solenoid Valve, Base Mounted, SY3000/5000/7000/9000

                                          5-Port Solenoid Valve, Base Mounted, Clean, 10-SY3000/5000/7000/9000

                                          Vacuum Release Valve w/Restrictor SY3000, SY5000 (24 V DC)

                                          3-Port Solenoid Valve, Elastic Material Seal, Pilot / Poppet Type, Body Ported, Rechargeable Battery Compatible

                                          3-Port Solenoid Valve, Elastic Seal, Pilot / Poppet Type, Base Mounted, Rechargeable Battery Compatible

                                          Intrinsically Safe Explosion-Proof Structure Certified (Japan) 5-Port Solenoid Valve, Base Mounted, 51-SY5000/7000/9000

                                          Individual wiring manifold, direct acting 3-port valve M3PA/B series, electromagnetic valve, unit

                                          Vacuum Release Valve With Throttle Valve SJ3A6 Series

                                          5-Port Solenoid Valve, Base Mounted, Single Unit, Rechargeable Battery Compatible, 25A-SY5000/7000 Series

                                          CAD
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          • 2D / 3D
                                          Days to Ship 15 Day(s) 15 Day(s) or more 15 Day(s) or more 15 Day(s) 15 Day(s) Same day or more 15 Day(s) 15 Day(s) 15 Day(s) or more 15 Day(s) or more 15 Day(s) or more 15 Day(s) or more 15 Day(s) or more 15 Day(s) 15 Day(s) 15 Day(s) 15 Day(s) or more 15 Day(s) 15 Day(s) 20 Day(s) or more 15 Day(s) 26 Day(s) or more 15 Day(s) or more 15 Day(s) 15 Day(s) or more 15 Day(s) 14 Day(s) or more 15 Day(s) or more 26 Day(s) or more
                                          Number of Ports5-Port Valve5-Port Valve5-Port Valve5-Port Valve5-Port Valve3-Port Valve5-Port Valve5-Port Valve3-Port Valve3-Port Valve5-Port Valve3-Port Valve3-Port Valve5-Port Valve5-Port Valve5-Port Valve3-Port Valve3-Port Valve5-Port Valve5-Port Valve5-Port Valve5-Port Valve3-Port Valve3-Port Valve3-Port Valve5-Port Valve3-Port Valve3-Port Valve5-Port Valve
                                          ApplicationSingle UseSingle UseSingle Use / Unit for Manifold MountingSingle UseSingle UseSingle UseUnit for Manifold MountingSingle UseSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingUnit for Manifold MountingSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingSingle UseSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingUnit for Manifold MountingUnit for Manifold MountingSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingUnit for Manifold MountingSingle UseSingle Use / Unit for Manifold MountingSingle Use / Unit for Manifold MountingSingle UseUnit for Manifold MountingSingle Use / Unit for Manifold Mounting
                                          Switching Type2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center2-Position Exhaust / 3-Position Closed Center2-Position Normally Open / 2-Position Normally Closed2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Exhaust2-Position Normally Open / 2-Position Normally Closed2-Position Normally Open / 2-Position Normally Closed2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center2-Position Normally Open / 2-Position Normally Closed2-Position Normally Open / 2-Position Normally Closed2-Position Pressure / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center2-Position Normally Open / 2-Position Normally Closed2-Position Normally Open / 2-Position Normally Closed2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Normally Open / 2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure Center2-Position Exhaust / 3-Position Closed Center / 3-Position Exhaust Center / 3-Position Pressure CenterOthers2-Position Normally Open / 2-Position Normally Closed2-Position Normally Open / 2-Position Normally Closed2-Position Exhaust / 3-Position Closed Center / 3-Position Pressure CenterOthersOthers2-Position Exhaust / 3-Position Closed Center
                                          VoltageDC24V / AC100V / AC220VDC24V / AC100V / AC110V / AC200V / AC220VDC12V / DC24V / AC100V / AC110V / AC200VDC24VDC24V / AC100V / AC110VDC12V / DC24V / AC100V / AC110V / AC200V / AC220V / AC24V / AC240VDC24VDC5VDC12V / DC24V / AC100V / AC110V / AC200V / AC220V / AC24V / AC240VDC12V / DC24V / AC100V / AC110V / AC200V / AC220V / DC5V / DC6V / DC3VDC12V / DC24VDC12V / DC24V / AC100V / AC110V / AC200V / AC220V / DC5VDC12V / DC24V / AC100V / AC200V / AC220V / DC5V / DC3VDC12V / DC24VDC24VDC12VDC12V / DC24V / AC100V / AC110V / AC200V / AC220VDC12V / DC24V / AC100V / AC110V / AC200V / AC220VDC24VDC12V / DC24VDC12V / DC24V / DC5V / DC6V / AC24V / DC3VDC24V / AC200VDC12V / DC24VDC24V / AC100V / AC200V / AC220VDC24V / AC100V / AC220V / AC24VDC12VDC12V / DC24V / AC100V / AC110V / AC200V / AC220VDC12V / DC24VDC24V
                                          Number of SolenoidsSingle / DoubleSingle / DoubleSingle / DoubleSingle / DoubleSingle / DoubleSingleSingle / DoubleDoubleSingleSingleSingle / DoubleSingleSingleSingle / DoubleSingle / DoubleSingle / DoubleSingleSingleSingle / DoubleSingle / DoubleSingle / DoubleSingle / DoubleSingleSingleSingleSingle / DoubleSingleDoubleSingle / Double
                                          Mounting OrientationDirectDirectManifold BaseDirectDirectDirectManifold BaseDirectDirect / Manifold BaseDirect / Manifold BaseManifold BaseDirect / Manifold BaseDirect / Manifold BaseDirect / Manifold BaseDirectDirect / Manifold BaseDirect / Manifold BaseDirect / Manifold BaseManifold BaseManifold BaseDirect / Manifold BaseDirect / Manifold BaseManifold BaseDirectDirect / Manifold BaseDirect / Manifold BaseManifold BaseManifold BaseDirect / Manifold Base
                                          Pipe Port TypeRc (R) / G / One-Touch PlumbingRc (R) / G / One-Touch PlumbingRc (R) / NPT / NPTF / GM / One-Touch PlumbingRc (R) / G / One-Touch PlumbingRc (R) / NPT / NPTF / G-MRc (R) / NPT / NPTF / GM / Rc (R) / NPT / NPTF / GM / One-Touch PlumbingRc (R) / NPT / NPTF / GMRc (R) / NPT / NPTF / G / One-Touch PlumbingRc (R) / NPT / NPTF / G / One-Touch PlumbingRc (R) / NPT / NPTF / GRc (R) / GM / Rc (R) / NPTF / GM / Rc (R) / G / One-Touch PlumbingM / One-Touch PlumbingRc (R) / NPT / GRc (R) / GOne-Touch PlumbingRc (R)Rc (R)Rc (R)M / Rc (R) / One-Touch PlumbingMRc (R)
                                          SpecificationsDrip-Proof / Lubrication FreeDrip-Proof / Lubrication FreeDrip-Proof / Lubrication FreeDrip-Proof / Lubrication FreeLubrication FreeStandard / Drip-Proof / Lubrication Free / Low CurrentDrip-Proof / Lubrication FreeStandard / Lubrication FreeStandard / Drip-Proof / Lubrication Free / Low CurrentStandard / Lubrication FreeLubrication Free / Low CurrentStandard / Lubrication FreeStandard / Lubrication FreeLubrication Free / Low CurrentDrip-Proof / Lubrication FreeStandardStandard / Lubrication Free / Low CurrentStandard / Low Vacuum Compatible / Lubrication FreeDrip-Proof / Lubrication FreeStandardLubrication FreeLubrication Free / CleanroomStandardLubrication FreeLubrication FreeLubrication FreeLubrication FreeLubrication FreeLubrication Free
                                          Status at Power OffSelf-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return)Self-Recovery (Spring Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-RetainingSelf-Recovery (Spring Return)Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Recovery (Spring Return)Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Recovery (Spring Return)Self-Recovery (Spring Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Recovery (Pressure Differential Return)Self-Recovery (Spring Return)Self-Recovery (Spring Return)Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)Self-Recovery (Spring Return)Self-Recovery (Pressure Differential Return)Self-Retaining / Self-Recovery (Spring Return) / Self-Recovery (Pressure Differential Return)
                                          Plumbing Thread Nominal1/81/41/2 ~ 3/8M51/81/2 ~ 3/8-M51/2 ~ 3/81/8 ~ M5M31/4 ~ 1/8M3 ~ M51/2 ~ 3/81/4 ~ 3/81/2 ~ 3/81/4 ~ 1/81/8 ~ M51/4 ~ M5M51/2 ~ 3/81/2 ~ 3/8-1/2 ~ 3/81/2 ~ 3/81/4 ~ 3/81/8 ~ M5M51/4
                                          PlumbingDirect PlumbingDirect PlumbingSub-Base PlumbingDirect PlumbingDirect PlumbingDirect PlumbingSub-Base PlumbingDirect PlumbingSub-Base PlumbingDirect Plumbing / Sub-Base PlumbingDirect PlumbingDirect Plumbing / Sub-Base PlumbingDirect Plumbing / Sub-Base PlumbingSub-Base PlumbingDirect Plumbing / Sub-Base PlumbingSub-Base PlumbingDirect Plumbing / Sub-Base PlumbingDirect Plumbing / Sub-Base PlumbingDirect PlumbingSub-Base PlumbingSub-Base PlumbingSub-Base PlumbingDirect Plumbing / Sub-Base PlumbingDirect PlumbingSub-Base PlumbingSub-Base PlumbingDirect Plumbing / Sub-Base PlumbingDirect PlumbingSub-Base Plumbing
                                          Applicable Cylinder Dia.(Ø)80 or Less100 or Less63 or less ~ 200 or less63 or less--80 or Less ~ 160 or Less-------80 or Less ~ 160 or Less80 or Less ~ 125 or less--80 or Less ~ 160 or Less-63 or less ~ 125 or less63 or less ~ 125 or less80 or Less ~ 125 or less---16 to 40-80 or Less
                                          TypeSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid ValvesSolenoid Valves
                                          Driving TypePilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type PoppetPilot Type SpoolPilot Type SpoolPilot Type PoppetPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type SpoolPilot Type PoppetPilot Type PoppetPilot Type SpoolLinear Motion PoppetPilot Type SpoolPilot Type Spool
                                          Connecting Tube DiameterØ6 / Ø8Ø8 / Ø10-Ø4 / Ø6Ø6-----Ø4 / Ø6 / Ø1/4 / ø2--Ø4 / Ø6 / Ø8 / Ø10 / Ø1/8 / Ø5/32 / Ø1/4 / Ø3/8Ø4 / Ø8---Ø6 / Ø8 / Ø1/4Ø4 / Ø6--Ø4 / Ø6 / Ø8---Ø4 / Ø6--
                                          Pressure Rating(MPa)-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7-0.1 to 0.7
                                          Seal TypeSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealStandard / Soft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealStandard / Soft SealSoft SealSoft SealSoft SealStandard / Soft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft SealSoft Seal
                                          CV Value0.33 ~ 0.490.63 ~ 0.930.18 ~ 3.30.13 ~ 0.190.4 ~ 0.580.8 ~ 3.6-0.130.8 ~ 3.30.14 ~ 0.330.04 ~ 0.120.68 ~ 0.770.086 ~ 0.0890.24 ~ 0.910.38 ~ 1.760.44 ~ 2.20.68 ~ 0.770.14 ~ 0.33-0.14 ~ 0.180.18 ~ 2.20.18 ~ 2.2-0.8 ~ 3.60.8 ~ 3.30.64 ~ 20.098 ~ 0.2520.05-
                                          Pilot Air SupplyExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalExternalInternal / ExternalExternalExternal-ExternalExternal

                                          Loading...

                                          1. 1

                                          Related Categories to Solenoid Valves