FSA Pro Track chainwheel, 144BCDx47T - black Bolt Pattern: 5-BoltChain Compatibility: 1/2" x 1/8"Chainring BCD: 144mmChainring BCD: 144mmChainring Speeds: singleChainring Speeds: trackChainrings Material: 7075-T6Chainrings Material: 7075-T6 AluminumComponent Color: BlackPosition: SingleTooth: 47t