Cassettes/Freewheels

Tested extensively by the Dutch National BMX Team, Damien Godet, Kory Cook, and numerous other elite racers, Box Two™ Freewheels combine durability with lightning-fast engagement. They feature nine, super durable pawls and are available in one of three choices -- 16, 17, or 18 teeth. To install, use the Park Tools™ FR-6 or other installation tool designed for single-speed freewheels with four notches that are approximately 32mm across measured inside to inside and 40mm outside to outside. FEATURES - 9 Pawls 108 [3.3°] Points of Fast Engagement

- 10-speed cassette sprocket - Offers a wide range of gearing options. - Lightweight sprocket carrier, it delivers smooth gear steps and precise shifting. - Ride anywhere with smooth and precise HG shifting

Shimano's Ultegra 9-Speed Cassette delivers pro-level shifting and durability. The computer-enhanced tooth shapes and tough cogs mean you can shift quickly, precisely and smoothly even under pressure.