Surly Single Cassette Cog 3/32" Splined 21t

Surly Single Speed Cogs.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 systemsFit Shimano freehub splinesSCM 415 hardened chromoly steelPhoto for color and material reference only