SRAM Force 10 Speed Rear Derailleur RD-FRC-A1 (Brand new old stock)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. 10 speed Compatible WiFLi option available Carbon fiber outer cage and magnesium inner link provide strength and light weight. 178g