For use with most Hand-operated Grease Guns and Air-operated Equipment Fits all 1/8" NPT threads. 6,000 PSI (414 Bar) Maximum Operating Pressure Hex Body for easy Installation and Removal Built-in Spring-loaded Ball Check Valve prevents Leak, Pressure Loss and Lubricant backup Four Hardened Steel Jaws for a Superior Seal and Longer Life Precision fit. Slight pushing action snaps Jaws onto fittings Zinc Plated for Maximum Protection against Corrosion