1.75" with unusual construction style. Front has crisp sepia photo from the shore looking out towards the extremely long pier. Tiny 1/16" tan dot at bottom is in the development of the photographic paper. The slightly domed celluloid is covered by a narrow brass rim which on the back is turned inward to hold in place a silver luster metal backing to the celluloid. Within the narrow channel which is formed is the heavy brass spring pin. N. Mint and only example we've seen.