Adall Calculator tool Adal Co 1908 Great Britain

Here is an early calculator device. Marked only “U.S.A. Patent Applied for”, dating it to exactly 1908 (Patent granted in 1909) according to the German website “calculating without electricity”. ADAL Co. was based in the UK and planned on selling their adding-made-easy device to the USA as well as to Europe. It is fully functioning with sings of age. The centre is brass, the back is aluminum. The original box must have been lost ages ago, giving it the nice patina (price accordingly). It measures 20 cm or 8 inches in diameter. On YouTube I found the video below, giving loads more background information on this interesting early calculator (this is not the one I am offering here, please see pictures).