Gruvlok Fig. 7377 is a flexible coupling utilizing double groove technology designed for high pressure piping applications. Fig. 7377 is specifically designed for use in mining, oil, gas, slurry, sludge, and hydraulic systems. The maximum working pressure for each pipe schedule and size are listed in the table below. Fig. 7377 is an ideal solution for high pressure applications, exceeding Anvil’s Fig. 7004 capabilities. See page 3 for double groove piping dimensions.