YOKOMO PLASTIC BEVEL GEAR DIFF. UNIT WITH ALUMINUM DRIVE CUP FOR YD-2 (Y2-500GSAA) It is a gear differential unit equipped with lightweight resin bevels and aluminum drive cup which are standard equipment of YD-2SX. By installing a plastic protector, wear of the aluminum drive cup is minimized, and throttle response is also improved by decreasing the clearance. #10000 silicone oil included.