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. Specification: Material: Stainless Steel Bayonet Connectors for 8mm(inner diameter) hose Type: PH20 PF20 - 1/4" BSP Female Thread connector Type: PF20 Package Includes: 20pcs Air Line Hose Fittings ( 10pcs PH20+10pcs PF20 ) Note: Please allow 1-3mm error due to manual measurement, make sure that you do not mind before you bid. Due to the different monitor and light effect, the actual color may be slightly different from the picture color.