... of the tube in which it fits) 1/8", 3/16", 1/4", 5/16" and 3/8".2.Three ... Four diaphragm materials. fluorosilicone, Viton, silicone and EPDMFunction:1.Prevents damage to equipment, pumps, and flow systems ... backflow2.Tubing barbed check valves are for an inert high purity smooth and clear flow path. 3.Use ... bag and wrapped, cased in small carton 1/4"PVDF VITON Ozone Resistance barbed plastic check valve