From the toughest World Cup courses to the smoothest bike paths, SRAMR PowerGlide II cassettes bring the right combination lightweight materials, durable construction and precise engineering to the ride. Get the same reliable, lightweight performance BlackBox racers enjoy. Tested on the pro circuit. Proven on the podium. SRAMR PowerGlide II 9 speed cassettes meet the demands of mtbers everywhere from elite racers to weekend trail riders. Option 1:: 11 34T, Option 2:: 11 32T. Recommended Chain:: PC 991, PC 971, PC 951. Lock Ring:: Anodized Alloy. Spider Type:: Alloy, 11 325 11 346 Sprocket Type. Finish:: Blast Chrome Plated. Ratios:: 11 32, 11 34.