e*thirteen Helix Race Alloy e*spec Crank Arm Set - DUB, 12mm Offset, 155mm, with Self Extractor, BlackA high performance, weight optimized alternative to carbon fiber, for riders who prefer alloy cranks. These 24mm ISIS interface cranks are engineered for compatibility with Bosch Gen 4, Brose S Mag, TQ HPR 50, Fazua, Yamaha, Maxon, and Specialized Brose motor systems. They come in short lengths starting at 155mm for improved pedal clearance and are tested to E Enduro standards. Product Specifics Color: Black Crank Length (mm): 155 Pedal Spindle: 9 16"