Quick connect 1/2 inch fitting. Fits some Eagle compressors. Tubelok Eagle 3738 Fitting.
Female threads are NOT NPT. Fits some Conrader unloaders and check valves. Designed for Eagle Wood Industries compressors.
Eagle didn't flare or use farrell fittings on their pump lines. The 1/2 inch line was cut square and inserted into this fitting. Metal grippers and O Ring makes the seal.