Marathon Industries 60011 - 2 Pk .75 in. Replacement Precision Ball Bearings 3&#47;4&#34; Precision Ball Bearings &#45; Qty 4. Made of Hardened Steel &#45; Double Inner&#45;Raced. Completely Sealed &#45; No Need to Grease. Ideal for Heavy Duty Loads&#44; Every Day Use&#44; Environments with Dust and Debris. 1&#45;3&#47;8&#34; Outside diameter.