Quick & Simple Connection. Proprietary Locking & 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 and Struggling with Stuck-On Couplers. If a Fitting becomes Pressurized, just Depress the Thumb Lever and 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!