TheOne Up Top Chainguide will help you eliminate dropped chains forever and more than double your chainring life. At only 40g the OneUp Chain Guide is incredibly lightweight, and can save you money in less than a season. The first chain guide designed to be both Oval and Boost compatible. As a Narrow Wide ring wears, over time the teeth thin and loose their chain retention ability, leading to more dropped chains. Installing a OneUp guide means you now only have to replace your chainring when the driving faces have worn out, which typically doubles your usable chainring life. Buy less stuff - Work Less, Ride More.One Up Top Chainguide FeaturesEliminate dropped chainsAlmost every EWS pro runs both a chainguide and narrow wide chainringBack plate cut from 8mm thick 7075-T6 aluminumBoost and oval chainring compatibleTool-less upper guide flip7.5mm of chainline adjustmentCompatibility with chainrings from 26-38tSingle tool install without removing your cranksMount: ISCG-05Weight: 40g