RAUPEX R-20 connections are for use with RAUPEX pipes and PRO-BALANCE manifolds and circuit isolation valves (article no. 302047-001). 3/8, 1/2 and 5/8 in. fittings include insert with O-ring, split brass ring and compression nut. 3/4 in. fitting includes R-20 x 1 in. bushing, 3/4 in. insert with O-ring, split brass ring and compression nut.