Quick & simple connection. Proprietary locking and quick-release mechanism, the coupler locks-on and creates a leak-proof seal. Innovative design enables quick release coupler to firmly latch onto the grease fitting, enabling hands-free greasing. No more fighting & struggling w/ stuck-on couplers. If a fitting becomes pressurized, just depress the thumb lever & release the coupler. No more broken-off fittings. No spurts or splashes when disconnecting. The waste and the mess are gone! A clean work environment at all times!