Box Two 4-Bolt Chainring (Black) (40T) - BX-CR144B40T-BK
Box Two 4-Bolt Chainring (Black) (40T) - BX-CR144B40T-BK, BOX Cosine Chainring. Features: CNC machined 6061-T6 aluminum with rounded tooth profile to reduce chain wear Specs: Ring Type:single Armx BCD:4x104mm Teeth:40t Color:black