I used to work at a Raleigh Pro Shop in the 1970s and the store had one to size up customers. A motor raises and lowers the seat and bars. The switch is under the front of the stem. You can see that in the photo. 3 position: up, off, down. There is a ruler on the side that reads in frame sizes. It came with a set of dropped bars and narrow seat. And a large adjustable t-square so once you had a customer set up on this sizer, you could transfer the measurements (seat height and seat to bars distance) to a bike they bought. We could write down the measurements on an order form and the mechanic could adjust the bike to match so it was ready at pickup time. It was a useful sales tool. The pedals turn and have minimal resistance (under 2 watts). On cold winter days I'd sit on it and pedal to keep warm. Or sit on the radiator in the store and watch traffic. Usually when biz was very slow and the boss was away.