Before the start of the first World War, the CF Martin company started building ukuleles. The first production models appeared in 1916. In 1920, Koa wood was used, which this model is constructed of. This instrument does not carry a serial number, but since it is made of Koa, it has to date after 1920. It also has nickel plated patent turners, which appeared in 1923.
The C.F. Martin logo is stamped on the back of the headstock, which changed to a decal in 1932. Bar frets were used until 1934.
I am assuming this instrument was built in the late 1920's.
This is a very nice instrument in great condition for it's age. The body is entirely Koa with a mahogany neck and Brazilian rosewood fingerboard. The bridge is Koa with a wooden saddle insert, possibly also Brazilian rosewood. The bar frets have very little wear.