Hallbauer 4-Jaw Professional 120/NPT Hydraulic universal Grease Couplers The unique action of Hallbauers 4-Jaw Universal Grease Couplers make them highly reliable tools tht ensure a professional job on everyday lubrication tasks. Unlike competitive couplers with a triangle or square connection, the exculsive nozzle pattern of the Hallibauer coupler forms a tight, safe grip on round grease head fittings. The results, Maximum grease is delivered into the fittings, even in high pressure applications. Case Hardened Steel Jaws and Case Safely handle up to 20,000 PSI