It had a lever to engage the outside hack wheel if you got into mud or sand. It did work very well when needed, but I rarely ever needed to engage it. On the road, that made it even slower!
I did like having a spare wheel/tire mounted on the rear of the hack...it fit any of the 4 wheels. I also liked the shock absorber style front suspension.
But the small amount of chrome bits rusted easily and the cheap pot metal everything else was made of corroded badly. After one winter storage, the bike looked like it was 40 years old!