Performance: Normal performance under 25 Celsius to 60 Celsius,Strong resistance to acid, , salt corrosion Application: Check valve is used in fluid system to prevent reverse flow fluid, or used in pneumatic system to prevent reverse flow of compressed airOpening pressure: less than 0.5 Kpa. Maximum back pressure: 0.3 MpaMaterial, safe and nontoxicStrong resistance to acid, , salt corrosion colour:Black+whiteMaterial:ABSsize: Diameter: 10mm/0.39 inch, length: 43mm/1.69 inchPackage Contents:4 x Check ValveOnly the above package content, other products are not included.Note: Light 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.