Manufactured using a high grade C45 Medium Carbon Steel outer ring and rear face with a recessed CNC machined 2024 aluminium Inner front face for weight reduction. The outer steel section of the rear sprockets have a black polished finish and the inner aluminium face has an ELOX finish in individual OEM colours. REAR XTREME ALLOY/STEEL SPROCKET- 52T BLACK/BLUE YAMAHA YZ/YZF/WRF 125-450 99-25