There is a notable new post over at the uncomfortable chair.
A vintage L. & C. Hardtmuth No. 43B leadholder is featured. One end holds a red lead, and the other a blue lead.
Though unusual, there are other examples of this category. Leadholder.com shows a 1948 red and blue Caran d’Ache Fixpencil 33 at the bottom of this page. The book Pencils has a two page spread on double-ended red and blue leadholders. And, Autopoint in the US continues to make double-ended red and blue mechanical pencils, as previously featured.
Still, the 43B appears to be unique in supporting wide diameter leads. (5.8mm is cited.)
Are there any other such mechanical pencils or leadholders out there, whether new or vintage?