The Grip & Grease Lock-on Grease Coupler (944IRV) is a 2 in. locking coupler with a patent pending pressure relief valve. It features a hardened locking ball and cage assembly that stands up to the rigors of 10,000 PSI again and again. The integrated pressure release valve fits most grease guns, zerks and accessories and is ideal for use with both cordless and air operated grease guns.
Link: Grip & Grease