This tri-clamp, single pin heavy duty clamp, with cross hole wingnut is made of stainless steel 304. Wingnut tightened to 25 in. lb. of torque. Service pressure ratings are based on the following parameters: matching elastomer gaskets and weld ferrules properly aligned and assembled with the clamps tightened to required torques. Tests are done hydostatically with no water hammer or shock loads. Please not the pressure raetings of the described unions may be above the recommended pipe line operating pressures.