4-arm, 104 mm BCD, aluminium 7075 T6, black SB-packaged, for MTB single chainsets The revolutionary chainrings from O.Symetric Non-circular shape for a 10% performance increase, better acceleration. 10% reduction in muscle lactic acid production, no other chain length necessary. Number of teeth 34 Item type attachment 4-hole Area of use MTB Main colour black Bolt circle diameter 104 mm Rear gears 10-speed