Lumbar roll backrest supports the lower back and spine. Softly curved upper edges reduce stress on pressure points by gradually tapering away from user. Unique center channel averts pressure on spine. Helps to maintain the spine's natural S-shaped curve. Contoured TherasoftÂ® material keeps its shape. Nonabrasive, antistatic, washable direct support to the â€œsmall of backâ€ region. Elastic strap fits any chair.