Renthal Rear Aluminum Sprocket Hard anodized 224U-520-49GPHA All rear sprockets are the ultralight design making them 66% lighter than steel, yet incredibly durable CNC machined from a specially enhanced 7075 T-6 aluminum alloy Machined self-cleaning mud grooves at each tooth to help increase wear resistance #1 sprocket used in supercross, motocross and offroad throughout the world Silver available for all models; black, blue and red anodized finish available for certain models All rear sprockets are the ultralight design making them 66% lighter than steel, yet incredibly durable CNC machined from a specially enhanced 7075 T-6 aluminum alloy Machined self-cleaning mud grooves at each tooth to help increase wear resistance #1 sprocket used in supercross, motocross and offroad throughout the world Silver available for all models; black, blue and red anodized finish available for certain models