Lens here was made by the Buhl Optical Company U.S.A. On the rim of the outer lens reads, \" Elm manufacturing company Hastings on Hudson New York 15.5 inch EFL Buhl Optical Co. Pittsburgh, Pa. U.S.A.Lens has a total diameter of 4 inches. The side with the rim is a total of 5\" The length of the lens is 4.74 weight 2lb 5 ozI have no idea of the age of this lens.
From the internet:The Buhl Optical Company was started in Pittsburg, Pennsylvania in 1930 by Dr. Jacob Stapsy. They were a leading maker of lenses and during WWII, they made gun sight lenses for the Air Force and other lenses for other branches of the military. They later focused on projection lenses, overhead projectors, spotting lenses, etc.
Please let me know if you have questions. I can combine shipping.

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