The TopChair-S is the only electric wheelchair that can climb several stairs without requiring a human companion and without the attachment of a fixed framework. To this end it has an innovative dual-motion system, with wheels and caterpillar treads. When climbing stairs, the seat of the wheelchair remains in a horizontal position independent of the inclination. Plain bearings from igus® are used for the movement of the front and rear wheels. Thanks to them, there are no problems with wear or corrosion.