This combination provides the benefits of stability and even pressure distribution without constricting blood circulation, lessening the risk of decubitus ulcer development. The Molding Foam Cushion’s convex bottom reduces “hammocking” in sling wheelchairs. Posey’s Sure-Grip vinyl cover is waterproof, odor-resistant, and helps reduce forward sliding. The zippered outer cover removes easily for laundering. Meets CA #117 flame retardancy standards.