1" x 1-1/4" Female/Male threads check valve. Silicon bronze cast body and silicon bronze cast poppet. Silicon bronze components contain less than .05% (1/20 of 1%) lead. check valves furnished with Buna-N O-ring, stainless steel spring, stainless steel washer, and stainless steel locknut. All check valves have a working pressure of 400 P.S.I.