A therapist favorite! The ComfySplints Hand Thumb Orthosis (HT-101) is uniquely designed to support the thumb without stressing the web space between the index finger and the thumb known as the “Thenar Eminence”. Size Chart Adult - 7"-8" Wrist to tip of middle finger, 12 1/2" total length. Adult Large - 8" and above Wrist to tip of middle finger, 13 3/4" total length. Adult Small - 6"-7" Wrist to tip of middle finger, 11" total length.