The Model G28 Hinged Grooved Coupling is designed for quick connect and disconnect services. The housing segments are hinged with a lever handle for easy assembly. The use of the split pin can secure and prevent the accidental opening of the coupling (dangerous at higher pressures). The Model G28 can be used in a wide variety of applications with standard rolled or cut grooved pipe (working pressures vary). Housings 1-1/2"- 4" (40 mm - 100 mm) feature a smooth outer surface, housings 5" - 10" (125 mm - 250 mm) feature a cross-ribbed design for added strength. Standard gasket: Grade 'E' EPDM or Grade 'T' Nitrile. Standard surface finish: Black electro-deposition coated.