These Fittings are From Production Runs That Supplies Peterbilt,Mack, Kenworth & Freightliner ! For Use On Compressors With Integral (1"-14 )Threaded Fittings On Head. Blue Used On Suction (Low) Side, Female 1 X 14 Threads, To Allow Hook Up of Suction Hose(#10 O ring fitting) and Servicing of System.
