Asahi/America valve gaskets offer a unique double convex ring design that gives optimum sealing with only one third the torque commonly required with flat faced gaskets. Asahi offers EPDM gaskets from 1/2" to 12"; PTFE-bonded EPDM gaskets in sizes from 1/2" to 12"; and PVDF-bonded EPDM gaskets from 1/2" to 10".