Face, it. If you are here, you are into a very esoteric and early part of fountain pen history.
We need a lot more information.
I have come across, but not owned, a few early Esterbrook pens that are Paul E. Wirt related, and probably are Wirt products. Esterbrook Relief pens that appear to be Wirt products have been seen in a simple cone cap dropper filled pen, a screw cap dropper filled pen, a Wirt Simplicity filler style pen, and a Wirt lever filling pen. Pens would date to the 1903-1920 era. All bear the same model number 314.
R. Esterbrook Co. RELIEF 314 cone cap dropper filled
David Nishimura has shown a Wirt made Esterbrook Relief in the simple style of a Wirt 3 line imprint pen, dropper filled, topped with standard friction fit cone cap. The imprint reads R Esterbrook Co., Relief 314. It has an unvented nib and the Wirt underfeed “loop feeder.” Pictures courtesy of David Nishimura.
R. Esterbrook Co. RELIEF 314 screw cap dropper filled
August 2023, on ebay, an Esterbrook Relef was listed. It appears to be the same style section as the Wirt screw cap dropper filled pens. It has a Wirt feed, unvented Esterbrook Relief nib, and Esterbrook Relief imprint reading Esterbrook & Co RELIEF 314. (Permission requested – ebay user 2oo4dunwell)
R. Esterbrook Co. RELIEF 314 Wirt Simplicity filler
Luiz Leite also showed me an early Esterbrook Relief that has the Wirt Simplicity filling system. The Wirt Simplicity pen does not seem to have a patent. The Wirt pen was featured in Geyer’s Stationer in 1915. Also labeled R Esterbrook and Co Relief 314.
R. Esterbrook Co. RELIEF 314 Wirt lever filler
The Wirt/Esterbrook connection continued into the late 19teens or 1920s. This pen is a Wirt MHR lever filling pen. But again, with the Esterbrook Relief 314 imprint. This pen came to me without a nib or feed.
And a write up in “Office Appliances” volume 34, 1921 showing a bit of a connection between Esterbrook Relief and Wirt products.