The PowerStool has a seat that goes up and down along a track. You can lean on it with your elbows or sit on it to assist in getting from siting to standing or to get up off the floor if you fall.
It uses a Track Actuator from Firgelli Automations
https://www.firgelliauto.com/products/heavy-duty-track-actuator
They come in various stroke lengths - 20, 30, or 40 inches