Maintains minimum constant line pressure to help eliminate excessive pedal travel and create a much firmer and responsive pedal feel. The two pound valve is recommended for disc brake applications while the 10 pound valve is mostly used on drum brake applications. EMPI's residual pressure valves are made from billet aluminum and are color coded and marked for easy identification and in-line mount using standard SAE brake line fittings. ) 1/8" NPT Both Ends Easy Installation with 1/8" NPT Male / 1/8" NPT Female Threads.