I imagine that neither a Feather Super Pro or Light blade would work very well in a single edge safety razor since that would change the blade exposure too much. The Super Pro in a AC straight allows one to use a shallower shave angle which can be advantageous at times or just personal preference.I tried the Feather Super also and found it to be a bit of over-kill. I still can't see why anyone would need them as apposed to a regular Feather Pro or Schick Proline blade.