You see them in videos and pictures mostly from the past, like the 50’s and 60’s. you basically stand in place and this big belt is around your waist vibrating away. What were they called? What was their prupose?
You can find information about them as simply “vibrating belt” machines, like these:
They were supposed to help you lose weight.
I used one when my parents took me to a party and then locked me away when I was a kid in the 1970’s. I hopped on and kept going until I got the nearby scale to show that I lost one pound. It took about an hour and it may have been just brain trauma from being shaken so much but it seemed to work although the pound was back a little while later.