Crisp, clean, correct shifting, always: the most precise gear change in cycling is here with the Sram Force Rear Derailleur. The Sram Force Rear Derailleur takes advantage of Exact Actuation, an actuation ratio that delivers precise 3mm shifts in every gear along with the widest range of adjustment available, delivering the best 10 speed performance in the sport. The Sram Force Rear Derailleur is crafted with cutting-edge materials, including a unidirectional carbon-fiber outer cage and a magnesium inner link, resulting in an impressively light 178g weight.Exact Actuation means precise, even gear changes throughout the shifting range.Carbon-fiber outer cage and magnesium inner link give strength and light weight..Speeds10.MaterialAluminum B-Knuckle, Magnesium Inner Link, Carbon/Aluminum Cage.Weight178g.Technology Highlight(s)Exact Actuation.