This quick release check valve fits Mack and Navistar air brake systems and is sold individually, built as a replacement for those applications. Mounted near the brake chamber in the air line, it lets air exhaust locally during release rather than traveling back to the treadle valve, which shortens brake chamber response time.Interchanges:Navistar 1676745C1Mack 20QE2288Mack 5396-KN32041Mack 745-289714LQV-3626FeaturesQuick release check valve for air brake systemsSold as 1 eachTech SpecsSell pack: 1 Each