Skil-Care Wheelchair Rigid Wedge BaseWheelchair Wedge Bases provide a rigid foundation for wheelchair seating to maintain a neutral seating position with raised front. By elevating the front, residents are less likely to slide off the wheelchair. If the chair has a reclining back, the elevation helps maintain a proper 90 degree hip alignment. Available in three wedge heights 2 inches, 3 inches or 4 inches (in elevation). All models are 18 inches wide by 16 inches deep.