52mm radius-face bearing with 40mm bore.  OD spinning bearing that press fits onto Tilton hydraulic release bearing piston P/N 62-612 or collars of some mechanical TOBs.  Replacement bearing for Tilton hydraulic release bearing part numbers: 60-1000, 60-3000, 60-4000, 60-5000, 60-6000, 60-8000. Replacement bearing for TOB part numbers 62-020, 62-021, 62-022 and 62-063.