The wolf tooth stainless steel 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 ultra-durable heated treated and electropolished 416 stainless steel, this is a remarkable exercise in top-tier precision engineering. If you're looking for a single speed cog to outlast all others, this is a sure bet.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.