Wirt pens with special cases Overlays (Wirt gold overlays, Wirt silver overlays, Wirt mother of pearl and abalone overlays) Wirt pens with spiral casesHexagon and faceted casesUnusual case design with enlarged center Wirt Overlay Pens Overlay pens were precious. They will almost always be engraved. Similar pens, one very early two-piece overfeed, and one post 1903 underfeed. Wirt taper cap pen with all abalone slab overlay. Wirt pens with hard rubber “Cable Twist” or spiral pattern Wirt Faceted pens – Wirt hexagonal and ten sided The underfeed hexagon pen has an imprint for a patent I can’t identify. The smaller pen with the round cap has 10 sides and a typical single line imprint. The oversized pen has a typical two line imprint. Faceted pens appear to have been made for at least 20 years.. Wirt pens with unusual case with a large center portion This odd pen was found in the catalogs, shown here. The top pen has a three line imprint on the cap and underfeed to match. The spiral case has an overfeed. They are dropper fillers. Wirt Mottled hard rubber pens with taper caps Mottled hard rubber taper caps are much less common than black ones.