G-Style Coupler 1/2" FNPT 1/2" Body Steel Quick Release Coupler Milton 1815Milton 1815 1 2" NPT Female G Style Coupler Steel 1 2" female NPT Milton G style air compressor quick coupler fitting. This is a top quality quick coupler made in the USA and is constructed from steel so it will last longer than the cheaper couplers made from brass. Unlike others that only have 3 or 4 ball bearings to hold the plug end, this coupler has 8 ball bearings ensuring a long lasting, snug, leak free fit! This coupler has 1 2" female NPT