This is a WalkingPad Z1 treadmill:

https://www.walkingpad.com/collections/foldable-walking-pad/products/walkingpad-z1-under-desk-treadmill

This one has something moderately wrong with it, it is louder than advertised, with a continuous swishing sound. It is noisy enough that I do not want to bother my coworkers by using it in our very quiet shared office, but if you want it for walking exercise in a context where some noise is OK it works fine mechanically.