Sram EX1 Crank arms, 170mm, NEWSRAM EX1 Crank arms, NEW Length 170mm Lightweight, durable, stiff and designed specifically to work with Bosch and Brose mid ship motors, SRAM's EX1 crankarms are purpose built for the high torque E MTB environment. Proven SRAM technologies adapted for the demands of midship motor E MTBs Compatible with Bosch, Brose and Yamaha bottom bracket interfaces Arm Material: Aluminum Colors: Black Bottom Bracket Interface: ISIS