Prevost ISI 061201 - The Prevost ISI, push button, safety couplers are designed for ease of use, reliability, durability and safety. The composite nylon body and nitrided steel components are engineered to withstand significant impact. The push button design makes for effortless coupling. The two stage connect/disconnect vents ""downstream"" air before disconnection eliminating ""hose-whip"". Prevost IRP 066251- Prevost's plugs are machined to very tight tolerances and exposed to a chemical hardening process (nitriding) that gives the Prevost plugs exceptional durability and leak-free performance. In industrial production, or in the home-shop the Prevost line of couplers and plugs are a reliable asset. Makes a great gift!