Direct Fit QR-1 Quick Release Valve: Features 3/8" NPT supply port and dual 1/4" NPT delivery ports for efficient air brake operation in heavy-duty truck and trailer systems. Durable & Easy Mounting: Compact body with 1.5" center-to-center mount hole spacing and 0.34" mounting holes; rugged for long-term use in harsh environments. Reliable Air Control: Zero PSI crack pressure ensures rapid exhaust of air from brake chambers, optimizing brake release response and safety. Industry Standard Threading: All ports with NPT threads for secure, leak-resistant installation compatible with a wide range of brake systems. Trusted Brand Replacement: Includes 1 valve; replaces over 60 part numbers across Bendix, Automann, Haldex, Navistar, Caterpillar, Freightliner