Standard Offset - This crank model is most suitable for Bosch gen 2/4 systems and Yamaha PW-X systems (not compatible with Bosch gen 3 BNI spindle interface).
Narrow Offset - This crank model is most suitable for Brose systems may also be used as a narrow Q-factor option on Bosch systems if there is adequate frame clearance (not compatible with Bosch gen 3 BNI spindle interface).