And, as it is self-driven, Jacob's Ladder doesn't need to be plugged right into a wall outlet. The machine by itself is produced from welded tubular metal with sound maple climbing rungs, so it's very strong. This device is really a stair climber, elliptical and treadmill all in a single. https://louisugwjd.bloguetechno.com/the-basic-principles-of-stair-climbers-70093279