Motorcycle Front Sprocket For GasGas MC EC EX ES 125 250 300 350 450 500 Fit For GasGas 125MC 250EC 250MC 300EX 350 500 ES 250EX-F 450 EC-F EX-F MC-F offroad enduro motocross bikes matched with standard 520 drive chain systemGASGAS CNC machined tooth profile meshes tightly with 520 chain to avoid chain skip, jump reduce transmission running noise Case hardened carbon construction delivers superior wear resistance for muddy trail, hill climb race track heavy-duty use Accurate spline size mounting dimension match engine output shaft for plug-and-play installation without Optimized tooth surface hardness lessens chain abrasion, extends overall life of full drivetrain assembly