Rapid action Bench Type Bearing Packer for use with Grease Guns. Non threaded top cone for fast placement of bearings. The design incorporates grease nipple on the outer shaft, which easily adapts to the grease gun coupler.suited for bearings with a min. inner diameter of 1/2" (12 mm), to a max. outer diameter of 6" (150 mm) and height from 3/8" (10 mm) to 2" (50 mm)