Key Features: Great value Alivio M3100 rear derailleur offering crisp performance on- and off-road for 9-speed drive trains,Shadow design with smooth skid plate surface features a super low profile design that reduces the risk of damage from trail side hazards,Wide link design increases rigidity and service life,Alloy body and outer link leads to lower weight without compromising strength and durability,11-tooth pulleys for reduced pulley wear and chain noise,Advanced light action design with low friction fluorine coated link pivot bushings,For use with 32 to 36 tooth low rear sprockets, total capacity 45 teeth,Top-normal swing design,Compatible with 9-speed Hyperglide sprockets.