Pencil Leads for Mechanical Pencils (Rayleigh SS6)

Different sizes of pencil leads for retractable mechanical pencils. The brown box on the end also contains tiny erasers. These can either be given as a whole lot or separately. Just state your need. (My father was a Work Study Civil Engineer and used these for his technical drawings.) These are not locality confined as I could post them (so long as I don't have to get to the Post Office too often).