Spring Loaded Activation Trigger: Simply depress the trigger when locking on or releasing the coupler onto the Zerk.Four Hardened Spring Steel Jaws: Resilient under high pressure, fitting all DIN and SAE specification Zerks.Small Diameter Front (16 mm), to help fit most recessed Zerks.Leak Free, High Pressure Seal nipples: Long lasting TPU seal reduces leakage.No need to hold while greasing: Lock-on and free up both hands to operate your grease gun.Easy clip-off: regardless of pressure build up in the line. NO MORE stuck couplers.M10 Female Thread: Standard size fits most grease guns; pneumatic, manual and electric.Max Pressure: 10,000 psi (690 Bar)Patents US8955544, EP2531766, others on application