1.25" with covered tin back and bar pin plus faint imprint and 1898 patent date by maker Pin-Lock. Reverse has tiny fragment of cello that failed to fold under the metal back and this area has small stain mark that shows on the far left front edge of the button. Other than this small area the rest is clean. Bold text displays the camera name flanking a cut-away view of the apparatus. There is also a faint image of a hand touching a knob with very tiny text below the camera reading "One Turn Of Button Does It." Top of the button has tiny caption "12 Pictures In 12 Seconds." This early camera was made by the Western Camera Manufacturing Company from 1897 to 1899. It originally sold for three dollars and fifty cents. Other than one 1890s button by Kodak this is the earliest button we know of to picture a camera. Rare.