e*thirteen Helix e*spec Crank Arm Set - 165mm BOSCH Gen4-Brose S Mag-TQ HPR50 Self Extractor BLK MFPN=ZS56L-40-BLU Wolf Tooth Precision Headsets for

Wolf Tooth Precision Headsets for Trek Knock Block are machined in the USA out of aircraft grade aluminum with superior sealing for protection against the elements

Designed for use with SRAM Boost cranksets with 55mm chainlines

Direct mount forged then CNC machined 7075-T6 aluminum chainring

PowerLock chain connector features Flowlink technology to provide superior chain-guiding and increased longevity

Finish Line's Showroom Polish & Protectant with Ceramic Technnology  delivers maximum luster repels water and prevents grime buildup

e*thirteen Helix e*spec Crank Arm Set - 165mm BOSCH Gen4-Brose S Mag-TQ HPR50 Self Extractor BLK MFPN=ZS56L-40-BLU Wolf Tooth Precision Headsets fore*thirteen Helix e*spec Crank Arm Set 165mm BOSCH Gen4 Brose S Mag TQ HPR50 with Self Extractor Black. Helix Core cranks provide an e bike drivetrain upgrade with high end features and aesthetics at an exceptional value. Forged for e Enduro strength with alloy self extractor bolts pedal washers and molded impact boots. 24mm ISIS interface models are compatible with Bosch Gen 4 Brose S Mag TQ Fazua Yamaha Maxon and Specialized Brose motor systems.