The FS44L-V3M has LED's for on footswitch indication of current active feature. This footswitch is for the V3M head and V3MC combo.
The FS44L and FS44L-V3m footswitch are functionally the same footswitch with only the switches labeled to match the product features for the switch.
Please call if you have any questions about choosing the right footswitch compatible with your Carvin amp.”
Earlier versions of the X100B or other X series heads and combos from the 1980's and 1990's are not compatible with this footswitch