COMPATIBILITY & SIMPLE TO USE: Fit seat post size: Options: 28.6mm, 31.8mm or 34.9mm. Compatible with Shimano, Sram, FSA, Campagnolo type braze on front derailleur. Simply clamp the adapter on the seat tube. STRONG: The adapter is made of high quality aluminum alloy AL6061 T6. It is also hardened by heat treatment. LIGHT: The bike adapter weights only 40g or 1.4 oz. I will not add a lot weight to your light road bikes or MTB. ADJUSTABLE: The height could be adjusted to ensure perfect gear changing position. Please note: The side adjustment is done by the bolts on the front derailleur itself.