AliMed Wheelchair Half Seat Wedge This device is the perfect answer to an uneven pelvis. The thick end (1.5") fits under one side of the pelvis, raising it to a neutral position and evening out the weight-bearing area. This decreases tone in the trunk and increases trunk elongation, resulting in an upright sitting posture, decreased leaning to one side, and decreased risk of skin breakdown due to unequal weight distribution. Aids feeding and other activities where posture and alertness are important. For best results, place the user's wheelchair cushion on top of the wedge.