5-Arm, for 10-/11-speed, 130 mm bolt circle, Aluminum 7075 T6, black SB-packaged, with ceramic-Teflon coating. The ceramic coating provides better 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 / lightweight / precise / maintenance-free! Number of teeth 42 Item type Attachment 5-hole Main color black Bolt circle 130 mm Rear shifting speeds 10-speed, 11-speed