I found this at a flea market yesterday and I couldn’t resist buying it. It’s a Sharp EL-805M “pocket” calculator that was released for sale in 1973 and discontinued in 1974.

This would have been a time when a Liquid Crystal display was a feature worth advertising on the front panel of the calculator (since this was the first calculator with an LCD).

Sharp was one of the pioneers of calculators using the DSM (Dynamic Scattering Mode) LCD (Liquid Crystal Display).  These DSM LCDs have the now unusual feature of silver-like reflective digits on a dark background, rather than the now common black digits on a light background.

http://www.vintagecalculators.com/html/facit_1106-sharp_el-805s.html

It was also from a time when instructions were included on how to use it. Notice the instructions for calculating 25 x 36, for example…

Undoubtably, the best 20 DKK I spent all weekend, given that the original price in 1973 was 110 USD.

For a peek inside, this site has some good shots, but it seems that it proves to be a challenge for automatic translators. There’s also a good history here.