The STEELMAN 99473 1/4-Inch NPT Steel Core Brass Coupler Pack is the answer to any workshop or automotive garage that uses multiple tools and air lines. Compatible with Milton or M type fittings, this pack includes 10 couplers and 10 plugs to let you have air tools and lines ready to go when work starts. The couplers are constructed of smooth operating brass that surrounds a durable and corrosion / rust resistant zinc plated steel core. The rugged plugs are likewise made of heavy-duty steel with a protective zinc plated finish. The coupler's brass slide operates smoothly and the knurled texture provides secure grip even under oily conditions or when wearing gloves. Both feature a high flow design that incorporates a wider than standard inner diameter that helps deliver more air to pneumatic tools providing you with noticeably increased power and performance. The coupler's hex shaped body can be easily tightened with any 11/16-inch end wrench and the threaded female end fits any 1/4-inch NPT threaded fittings. The plugs have a hex section that fits a 14mm wrench and have 1/4-inch male NPT threads.