Use Default Resolutions - Check this to use default number of faces.

U - Number of faces in the U direction. Can be set if Use Default Resolution is unchecked.

V - Number of faces in the V direction. Can be set if Use Default Resolution is unchecked.

Subdivision Object - Check this to make Subdivision object instead of triset.

Merge - Check this to merge all converted objects into a single Subdivision object.

Join - Check this to join faces that have edges near enough.

Distance - Maximum edge distance for joining faces.

Del orig. - Check this to delete the originally selected objects after conversion.