The Black Diamond Quick Connect Coupler is designed for use with hand-operated grease guns, delivering quick engagement and disengagement even under high pressure. Its compact "forward push" mechanism makes connecting and releasing easy in tight spaces, while heat-treated spring steel jaws provide a secure grip on the grease fitting. During engagement, the four jaws move inside a hardened coupler body that supports the jaws to help prevent deformation or damage under load. Threaded 1/8" NPT with a 5,000 psi working pressure.