Check valve (non return valve): Feature type : bolted cover, swing type, lift type, wafer type design disc : composition disc, metallic disc. Size range : 15mm to 400mm & above on request pressure rating : 150#, 300#, 400#, 600#, 800#, 900#, 1500#. End connection : flanged ends, socket weld ends, screwed ends & butt-weld ends. Mfg. Std. : bs-1868, api - 6d testing : bs - 6755-1, api-6d Material of construction : cast carbon steel (astm a 216 gr. Wcb, astm a 217 gr. Wc6, wc9), forged steel (astm a 105, astm a 182 gr. F22, f304, f316) cast stainless steel (astm a 351 gr. Cf8, cf8m, cf3, cf3m), alloy 20 to astm a 351 gr. Cn7m