Quick Couplings Hebei Hengyang Stainless Steel Products Co., Ltd. produces various quick couplings. Features: Quick connation Interchangeable completely between adapter and coupler Pressure-proof hydraulic pressure test 300 PSI for up to 4" and 200 PSI for 5" and up Materials: Stainless steel (investment cast)1/2"-6" Packing: BUNA-N(NBR) (or TEFLON, VITON on request) Specifications: Our couplings conform to MIL-AA-57326(MIL-C-27487) and are interchangeable with other products which meet this specification Threads: ANSI B 1.20.1(NPT) DIN 2999/259 BSP BS 21(PT)