All double cranksets can be converted for singlespeed/fixed gear use for an extra £10. This covers the cost of the Stronglight singlespeed chainring bolts required to convert it using one of the original 3/32" rings.
NB: If you have a pre-1980s French bike then you may have French threaded pedals, otherwise it's unlikely that you have to worry about this section.
TECHNICAL INFO & CONDITION:
Standard (9/16" x 20 tpi)