5-arm, for 10-/11-speed, 130 mm bolt circle, Aluminium 7075 T6, black SB-packaged, with ceramic-Teflon coating. The ceramic coating provides improved strength, durability, and abrasion resistance. The Teflon coating reduces chain friction by 80%, ensures significantly quieter running, and permanent lubrication improves shifting function. These chainrings are durable / light / precise / maintenance-free! Number of teeth 50 Type of item attachment 5-bolt Main colour black Bolt circle 130 mm Rear gear steps 10-speed, 11-speed