Accidents happen. With condenser lenses, that usually means a scratched or chipped lens. Small chips right at the edge of the lens and very minor scratches probably won't have an effect on the prints, but major chips and scratches will, in which case you need to replace the damaged lens.
As selected below, these are either brand new OEM condenser lenses or used condenser lenses in perfect condition - no scratches or chips. They can be used to replace main 6½" lower condenser lens in all Beseler 45M condenser heads.
The upper condenser is a different part and is listed separately.