This little gem is embossed on front: OTIS PATENT and on the reverse: 1851. The unusual feature is the curved metal top which is where the old lightning rod was passed through. Most Otis LRIs have a square opening, and frankly I don't know why this one has a curved opening. Color is a light SCA. This was formerly in the collection of Bill Dreggors and his late wife, Jo. Purchased in 1996.