Description: Made of heat treated hardened steel for strength and durability. Zinc plated finish for rust and erosion resistance. Spring loaded quick release couplers which should be used on the compressor so that the air is contained when the air tool is disconnected. When using the coupler(s) slide back the sleeve, push in the connector and then slide back the sleeve fully to lock in the connector. Enables tools and airlines to be quickly connected / disconnected. Reduces accidental airline disconnection. Materials: Stainless Steel SM20 - 1/4 BSP Male Thread Quick Release Coupler Type: PM20 Package Includes: 5 X Air Line Hose Fittings