The all new Ring-Pen Ultra supports a thin pen, pencil, marker or paint brush. Designed to help anyone with Arthritis, Carpal Tunnel Syndrome, Repetitive Stress Syndrome. Assist hand weakness, fine motor skills and reduces need to use pressure preventing pain and muscle cramps. General guideline for choosing sizes. Large will work for most men hands and larger womens hands. Medium will work for most womens hands and for smaller mens hands. Small is best suited for children. For right hand use only.