GIMBAL BEARING MERCRUISER, OMC, VOLVO PENTA New Gimbal bearing. Replaces GLM Part Number: 21900; Sierra Part Number: 18-2100; Mercury Part Number: 30-60794A4; OMC Part Number: 983937; Volvo Part Number: 3853807-0 Fits OMC Cobra and King Cobra Fits Mercruiser Bravo and Alpha Gen 1 and 2. Fits MC-1 / R / MR Fits Volvo Penta This is the greasble type. Your transom must have a grease zerk fitting.