Thanks, Bob.

So if I understand correctly, I can use any crank that uses the same length spindle as the M151 uses. Right?

Looking at the specs I attached to the OP, the spindle length is "D-NL (122.5 mm)". What does the D-NL mean? Can I choose anything that uses a 122.5 mm spindle, or do I have to match the D-NL part too?