The Allegheny 20330ZF is a 3-inch steel Mark I grooved coupling with golden zinc flake coating and a black BioLution gasket for tank trailer applications. This coupling provides a quick and secure connection for grooved pipe systems. Constructed from 10-gauge steel with zinc flake coating for corrosion resistance, the 20330ZF accommodates pipe misalignment and reduces vibration in tank trailer piping systems. Maximum torque for bolts is 30 ft-lbs.