Replacement Sight Glass Arg500 And Arg755 | Groco Arg-503 Groco ARG500 and ARG755 Replacement Sight Glass | ARG-503 Groco sight glass Fits Groco 1/2 in. NPT ARG-500 and 3/4 in. NPT ARG-755 bronze raw water strainer heads One-piece molded sight glass Includes drain plug and drain plug o-ring Cleans easily using only mild soapy water Strainer head to sight glass o-ring P/N 2-153 - sold separately Service Kit P/N ARG-1 - sold separately