SRAM Road 52 teeth 4 mm triple chainring are stamped from 7075-T6 aluminium with black hard anodized finish. Middle rings have PowerGlide ramps, outer rings have PowerGlide pins/ramps. Number of bolts: 5. 130 mm bolt circle diameter. Low weight and excellent strengthMade of 7075-T6 aluminiumMiddle rings have PowerGlide ramps, outer rings have PowerGlide pins/rampsBlack hard anodized finish130 mm Bolt circle diameter