The Wolf Tooth Aluminium Single Speed Cog utilises extra tall teeth for reliable chain retention when using a chain tensioner. Fitting perfectly onto any Shimano freehub, this cog is optimised for 9, 10 or 11-speed chains but will work with all chains.Machined in-house at Wolf Tooth\'s Minnesota HQ from high-grade 7075-T6 aluminium in a variety of vivid colours, this is a great way to add some flair to your beloved single speed.Compatibility:These will fit on any Shimano-type freehub spline (geared or single speed),Designed to work with any chain,Tooth width optimized for 9-,10-, and 11-speed chains.