The Wolf Tooth Stainless Steel Single Speed Cog are incredibly lightweight and aesthetically pleasing single speed cogs. They feature extra tall teeth for reliable chain retention when using chain tensioners, they are machined from 416 Stainless Steel billet with heat treating and electropolishing post processing for durability and corrosion resistance. They are reversible and feature a 4.5mm width at the base that won't dig into your freehub body.  Wolf Tooth Stainless Steel Single Speed Cog Features 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 Wolf Tooth Stainless Steel Single Speed Cog Specifications Design and manufactured in the Minneapolis, MN USA Made from hardened and electropolished 416 stainless steel Colors - Silver Weight - 16T - 30g, 17T - 32g, 18T - 35g, 19T - 38g, 20T - 40g