From Finland, a four wheel drive rough terrain powered wheelchair. The Chasswheel Four X combines four wheel drive with suspension and shock absorption to get through and over obstacles.

The Four X has a flexible chassis structure that allows each wheel to respond to contours in the terrain. This keeps all four wheels in contact at all times. The wheels themselves are each driven by an independent motor The entire package is fitted to a suspension system with shock absorption.

An adjustable seating systems allows for moving the seat backward or forward 25cm for adjusting center of gravity. This is particularly handy when going over rough time, negotiating steep slopes, or dealing with difficult weather conditions.

You can see images of the Four X in use at the Chasswheel website:
http://www.chasswheel.com/