The EX1 drive train was designed specifically for the demands of electric-assist mountain bikes: a wide gear range with bigger jumps between gears and sturdy components to handle higher torque loads. Liberal use of features found on SRAM's high end MTB parts provide high value, quiet operation and ease of service.Machined from case-hardened tool steelCogs are designed to work specifically with inner and outer chain links for precise up- and down-shiftsBig steps between cogs are suited for electric-assist riding, reducing double shifts and maximizing component lifeItem SpecificationsNumber of Speeds:8Range:11-48 SRAM EX1 XG-899 8 Speed Cassette Cassettes UPC: 710845793554