Awesome 18 Inch Iron Level in a Fitted Slide-Lid Case

One of the most unique iron levels I’ve come across, and the only one like it I’ve seen. 18 inch open-web frame with double plumbs and a level in nickeled vial housings. Kept over the years in what is probably its original wooden slide-lid case. All three vials are full and working. Circa 4th quarter of the 1800’s.