These Wolf Tooth aluminum single speed cogs feature extra tall teeth for reliable chain retention when using chain tensioners.Item weight: 23.5gCrafted with strong and lightweight premium 7075-T6 aluminumOptimized for use with 9,10,11 speed chains, but suitable for use with some 12-speed chainsReversible and 4.5mm wide at the base to help prevent cog from damaging your freehub bodyFits Shimano Hyperglide style freehub splinesNot compatible with Shimano Microspline or SRAM XD freehubsNot compatible with Campagnolo 13-speed chainsItem SpecificationsCassette Body TypeShimano HGDefined ColorGoldDrivetrain SpeedsSingle Speed 3/32"MaterialAluminumTooth Count20 Wolf Tooth Aluminum Single Speed Cog Driver and Single Cog UPC: 812719023030