Not a pocket calculator.....
.....I rescued it from a skip when I worked on a temporary research contract in the Geology Dept at Sunderland Poly/Uni in 1989
.....they were clearing out a lab to make room for some of those new-fangled computer thingies, probably BBC Micros
.....I said they should donate it to a local musuem
.....they said the paperwork would be too much effort
.....consequently I had a helluva job, and some strange looks, lugging it home on the train that night
.....it looks almost identical to the third picture down on this webpage
.....except it's a lot dustier, and with more cat hairs
.....it has cogs and wheels, dials and sliders to fiddle with, even a gear lever
.....it makes proper mechanical noises when you turn the handles
.....it probably does no more than add and subtract
.....it's made of solid metal
.....it weighs a ton
.....it makes a great doorstop, a tornado wouldn't shift it
.....y'know there's probably an app for that now, except the doorstop bit.............