4-Arm, for MTB, Mod. 17, for 2x10-speed, 104 / 64 mm BCD, 7075 T6 aluminum, black CNC, 100% compatible with Shimano XTR FC-M980 Technology HT3 7075-T6 aluminum chainrings with a titanium oxide electro-ceramic coating. This exclusive coating offers an ULTRA-HARD surface for a long service life (hardness: 1.5 to CT2). The coefficient of friction and abrasion has been significantly reduced (0.2-0.3) and offers noise reduction as well as excellent corrosion resistance. Number of teeth 30 Type of item Fastening 4-hole Area of use MTB Main color black Bolt circle 64 mm Rear gear stages 2-speed, 10-speed