[Function] Flat,non-patterned side is the inlet.Raised,patterned side is the outlet.You can blow to the check valve,the port where the gas can be blown is the inlet.[Features] The pipe port of the check valve is designed with a -shaped card slot, non-slip and non-toxic, with good airtightness and good adsorption performance.The non-return check valve is easy to install, convenient for you to unscrew and replace[Application]- Check valve is used in fluid system to prevent reverse flow fluid, or used in pneumatic system to prevent reverse flow of compressed , can be applied to automotive parts, machinery industry, household appliances, agriculture, etc.[Material]- way check valves are sturdy, wear-resistant and durable for long-term useOpening pressure: less than equal 0.5 KpaMaximum back pressure: greater than equal 300Kpacolour:WhiteMaterial:PVDFsize: Diameter: 1/4 inch / 6mm, length: 1.5 inch / 38 mmPackage Contents:24 x Check ValvesOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.