The Olivetti calculator works. It is boxed with the original instructions and was given away as a promotional item by AXA in the late 1990s\early 2000s. The Sharp ELSI MATE EL-8021 dates from the late 1970s and, although may not work, is a true collectors item. I've had the back off (it needs a second screw on the battery panel) to take a look. There are only three batteries vs. the four needed. I don't have any of the type used (they may not be made anymore) so cannot test whether it still works. For the purposes of this listing assume non-working.