The Mastercool 82374 Easy Connect Oil Injector offers users an excellent method for adding refrigerant oil or large amounts of UV leak detection dye to an A/C system. Users can add oil by allowing a vacuum to pull it in after the evacuation process, or use refrigerant to push it in by using the recharge system. The 'Easy Connect' model uses a ball-valve design attached directly onto the end of the A/C hose. The 82374 model includes a low-side coupler on the outlet hose and features a rugged, all-metal 2 oz. canister design.