Its narrow/wide tooth profile holds the chain tight and eliminates the possibility of the chain dropping when using a modern clutch rear derailleur. The oval chainring design is effective because the rider does not produce an even power output with a normal circle chainring. When using a standard circle chainring, the power consistency is only relative when the rider’s feet are pushing downwards. With an oval chainring, the power output is balanced and you will actually feel power being applied at all stages of the pedal rotation. Hope Oval Spiderless Retainer Chainring 32t Features Materials: Cnc Machined 7075 - T6 Aluminium Direct Mount: Hope Specific Tooth Profile:Narrow/Wide Intended Chainline:52-53mm (boost 148) Compatibility:9-Speed,10 Speed and 11 Speed Weight:62g (32T)