The Box Four Wide/Narrow chainring completes that package for the 1x8 system. It is the first 8-speed specific chainring designed to optimize chain retention when using 8-speed chains. The tooth profile and thicknesses are tailored to match the inside geometry of the unique Box Four chain. FEATURES - Our 8 is Enough Chainring - Forged & CNC Steel - ED Black Protection - Wide / Narrow 8s Specific - 104 BCD Compatible