Hope spiderless boost retainer ringspecially designed for use with hopes ldquoboostrdquo compatible mountain bike mtb cranksets, this spiderless boost retainer chainring adopts the direct mounting system and the ldquonarrow widerdquo tooth design. This tooth profile results in outstanding chain retention over the toughest trails, removing the need for a chain device on your bike. Made from cnc machined 7075 t6 aluminium, it runs quietly, reduces drag and it's ready for use with the wider chainline on ldquoboostrdquo type mountain bikes.featuresmaterial cnc machined 7075 t6 aluminiumfinish hard anodisedmount hope specific direct mountspeed 9, 10 and 11 speedtooth profile narrow wideintended chainline 51 53mm boost 148 narrow wide tooth profile designed to retain the chain without the need of a chain devicedirect mount retainer ring designed specifically for hope cranksetssaves weight without the need for a separate spiderable to run a broader range of smaller chainring sizesquieter drivetrain and less dragultra durable and increases longevityweight 26t 49g 28t 56g 30t 61g 32t 64g 34t 72g 36t 80gbuy hope components from chain reaction cycles, the world's largest online bike store.