Amana Tool uses only the finest industrial quality precision ball bearings available. Bearings are double steel-shielded for extra rigidity and to inhibit dust. A special high-performance, high-temperature grease is used for maximum life., #47772, diameter (D) 1-3/8, application trs-310 (Timberline), B 1/4, D 8mm, 47772 Metric steel ball bearing guide 1-3/8 Overall DIA x 8mm inner DIA x 1/4 height