1. Locking and Sealing: Upgrade jaw design snaps and quality sealing gasket, strong enough to lock zerk and prevent leakage, and easy to lock and release. 2. One Hand Operation: One handle with anti-slips design and smooth retraction mechanism allows one-hand operation, which is ergonomic and less labor-intensive. 3. One Hand Operation: One handle with anti-slips design and smooth retraction mechanism allows one-hand operation. Which is ergonomic and less labor-intensive. Once locks onto zerk fitting, it stays on and frees both hands to operate the grease guns. 4. Wide Compatible: Our grease guns coupler is compatible with most grease guns, mini grease guns, small grease guns ends, especially suitable for excavators, bulldozers, cars, large equipment in factories, tractors, harvesters, etc. 5.Once locks onto zerk fitting, it stays on and frees both hands to operate the grease guns.