Surly Single Speed Cog. Features: Designed as a singlespeed cog, but may also be stacked and used with 9-speed shifter. Multi gear use will result in slower, less crisp shifting than cogs designed for multi-gear systems Fit Shimano freehub splines SCM 415 hardened chromoly steel Photo for color and material reference only Specifications: Cogs: 13T to 22T Size: 3/32" (Single Speed) Material: Steel Color: Silver Weight: TBD