The LockNLube Grease Coupler XL is a longer version of the company's original leak-free, mess-free coupler. It features a sliding sleeve that’s operated by a thumb lever. Four hardened-steel jaws lock onto the grease Zerk, creating a leak-proof seal and preventing the coupler from coming loose. With almost 4" of reach, this grease coupler is especially suited for recessed Zerks such as those found on shielded PTO shafts, axles and U-joints. It releases easily, even under extreme pressure. The LockNLube XL will not pop off under pressure, says the company, and still releases easily with the thumb lever, even from recessed fittings, even when under extreme pressure. The LockNLube Grease Coupler XL fits all 1/8" NPT grease hoses and is compatible with all grease guns.