TheBurgtec ThickThin 104 BCD Chainring were given to elite riders such as Josh Bryceland, Marc Beaumont, and Scott Mears to ensure quality chain retention at the highest speeds. Burgtec ThickThin 104 BCD Chainring Features Available in 30T, 32T, and 34T Ratios Designed for the 104 BCD 4 Bolt pattern crank Use in conjunction with clutch rear derailluer for best results No need to use a chain device Designed and manufactured in the UK More info