This Dixon Air King AWR4 rubber washer is intended for use with sizes 3/8" to 1" two-lug Dixon Air King couplers and hose ends (not included) and prevents pressure leaks while the air or water line is pressurized. The washer's outer flange is 1-5/16" outside diameter and 3/16" thick, the washer's inner flange is 1-3/16" outside diameter and 7/16" thick, and the washer's inner diameter is 1-1/16". The black natural rubber washer has a maximum air pressure of 150 psi at 70 degrees F and an operating temperature range of -20 to +160 degree F. This rubber washer is suitable for use with Dixon Air King couplers and hose ends in air and water use in applications such as construction and mining.