These are the lightest weight and best looking stainless steel single speed cogs available. They feature extra tall teeth for reliable chain retention when using chain tensioners and 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 4.5 mm width at the base that won't dig into your freehub body. Compatibility These will fit on Shimano Hyperglide style freehub spline (geared or singlespeed). Not compatible with Shimano Microspline or SRAM XD freehubs. Designed to work with any chain through 12-speed Tooth width optimized for 9,10, and 11-speed chains Related products mate with these cogs for the ultimate singlespeed drivetrain Drop-Stop®chainrings If you are more concerned with weight than durability, check out our Aluminum Single Speed cogs. Tech Specs Weight:16T • 30g | 17T • 32g | 18T • 35g | 19T • 38g | 20T • 40g Material: hardened and electropolished 416 stainless steel Made in the USA [snippet name="Prop 65"] Patent and trademark information