This ten-pound residual pressure valves retain a minimum brake line pressure to help eliminate excessive pedal travel in drum brake systems. With drum brakes, a ten-pound valve is used to compensate for return spring tension and maintain wheel cylinder sealing in the drums. Residual Pressure Valves are made from billet aluminum and color coded for easy identification. Valves with fittings are supplied with two 1/8-27 NPT to 3/-24 inverted flare female fittings that will most domestic 3/16th hard brake line.