LockNLube Grease Coupler locks onto Zerk fittings. Grease goes in, not on the machine. World's best-selling original locking grease coupler. Rated 10,000 PSI. Long-lasting rebuildable tool. Locks on, does not leak 1/8" NPT compatible with all grease guns - battery, pneumatic, manual Grease goes in, not on, the machine World's original locking grease coupler. World's only rebuildable grease coupler. Lowest lifetime cost. Unique patented design. Locks on.....Stays on....No leaks! Four hardened spring steel jaws are resilient under high pressure - over 10,000 psi. Grease goes IN, not ON the machine. No more grease mess everywhere. Ends the waste. Ends the mess. Ends greasing frustration. Fits all Grease Guns - 1/8 NPT fitting. Fits all SAE and Metric Zerk fittings. Simply replace your existing coupler, click the orange button on the right to buy. Pressure locked? No problem. Easily releases from clogged fittings, even at extreme pressures. You know the grease is going in, even if you can&#039;t see the Zerk. You don&#039;t have to fight to get the coupler to release. Just push down the thumb lever to release.