MaxLINE 3/4" piping by 1/2" male NPT straight adaptor fitting (Part number M8005). This MaxLINE union is specifically designed for the MaxLINE 3/4" tubing made by RAPIDAIR and is great for adding regulators, filters, and other equipment in the middle of the air line that need a 1/2" male NPT hook up, also if your trying to hook something up that is not 1/2" you can always use a reducer to connect this fitting if needed. This fitting is made of solid brass and has a double o-ring seal for a no leak connection. Also is has split ring connections for easy disassembly if needed.