Chainring Range: Choose from 28-32 or 32-36t models.* Drivetrain Compatibilty: Internally shaped to accomodate even super-wide ratio cassettes and wide chainlines. Mounting Options: ISCG-05 only. Weight: Alloy SL: 105-109 g Carbon SLR: 86-90 g SL and SLR models have 28-32t or 32-36t options that share backplate and upper guide parts, but feature different bashguards: AMg SL and SLR 28-32t use bashguard "A" AMg SL and SLR 32-36t use bashguard "B" *CS is one size: 28-34t (uses bashguard "A")