316 Stainless Steel duo check valve. Stainless Steel spring loaded gates, 316SS disc, FKM seat and PTFE washer. Wafer design to suit ANSI 150 Flanges. These Duo Check Valves are easy to install and maintain and provide great in line back flow prevention in a wide range of applications. Face to face according to DIN3202-K3 / EN558-1. Suits ANS 150/300 & DIN PN10/16/25/40 flange standards.