With just a simple twist of the special self-inflating valve, the WonderRoll automatically inflates. It's easy to adjust the airflow to find the perfect comfort level for your back. Lean on your Wonder-Roll, and open the valve to set desired firmness and close the valve to maintain the support. It includes an adjustable strap to attach to any chair.The Wonder-Roll is the original self-inflating lumbar roll. Designed by our Physical Therapist CEO, the Wonder-Roll decreases strain and relieves low-back discomfort associated with sitting. It makes any chair ergonomically correct, and counteracts poor posture. With a twist of our special self-inflating valve, the Wonder-Roll automatically fills with air. Then with a simple adjustment of the valve the Wonder-Roll conforms to the shape of your spine for the perfect fit.