We offer Flexible Coupling Style 77s designed to provide a rugged mechanical joint for grooved end stainless steel piping systems, style 77s coupling sizes 1" - 4"/24 - 100mm are cast of ce8mn (duplex stainless steel). Coupling sizes ¾"/20mm and 6" - 18"/150mm - 450mm are cast of cf8m (316 stainless steel). Style 77s couplings come standard with wras-certified, grade "ew" epdm gasket material with approved microbiological resistance.