FSA PowerBox/SL-K Super Road ABS Chainring 53T 110ABS 4H N11. The FSA PowerBox/SL-K Super Road ABS Chainring is a high-performance component designed for use with FSAs modular crank systems. With its ABS interface and optimized tooth profiles it delivers crisp reliable shifting under load. Ideal for road cyclists and racers this chainring supports efficient power transfer and long-term durability in demanding conditions.