Hope oval spiderless boost retainer ringthis stunning model features a narrow wide tooth profile which holds your chain tight and eliminates the possibility of your chain dropping when using a modern clutch rear mech. Its oval design is ideal for producing more power output than with a normal circular chainring. When using a standard circle chainring, the power consistency is only relative when your feet are pushing downwards but with this model, the power output is balanced and you will actually feel power being applied at all stages of your pedal's rotation.features material cnc machined 7075 t6 aluminium finish hard anodised mount direct mount compatibility 9, 10 and 11 speed tooth profile narrow wideintended chainline 51 53mm boost 148 quieter drivetrain and less drag ultra durable and increases longevity weight 62g 32t modelbuy hope components from chain reaction cycles, the world's largest online bike store.