Apico steel rear sprockets are manufactured using an aerospace grade light weight C45 Medium Carbon Steel. Cad Designed for enhanced tolerances and CNC machined laser cut profile for improved weight reduction and strength throughout. A standard feature with all Apico rear sprockets are the clearing grooves around the outer edges of the sprockets. Theses help to remove any build-up of mud and reduce ware and additional stress to the sprocket. Finished with a Cataphoresis Electro Coating giving them a unique look and unrivalled anti-corrosive properties. CARBON STEEL REAR SPROCKET - BLACK BETA 125RR 2T 18-24 200RR 2T 19-24 250RR 2T 13-24 300RR 2T 13-24 250 X-TRAINER 20-24 300 X-TRAINER 15-24 350RR 4T 13-24 390RR 4T 15-24 400RR 4T 13-14 430RR 4T 15-24 480RR 4T 15-24 498RR 4T 13-14 500RR 4T 13-19 520RR 4T 13-14