There are two basic types of grooved coupling , rigid coupling and standard flexible coupling.Rigid coupling specifications:Maximum working pressure is 70°F(21°C): 500psi and 300psi in sizes 1½ ", 2½ ", 3 ", 4 ", 5 ", 6 ", 8 ", 10 "and 12", comparable to VICAULIC # 75GRINNELL #7000Groove rigid coupl
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