ACCOMMODATING SIZING - Now we have two sizes to accommodate all size arms. S/M for smaller arms (teens and average size woman) and L for larger arms. RIGID METAL STAYS - The Mars Wellness Ulnar Nerve Brace utilizes two rigid metal stays prevent the elbow from bending while still allowing for some movement GREAT FOR SLEEPING - The Mars Wellness Cubital Tunnel Brace for Sleeping is made of soft, comfortable foam material that allows your skin to breathe. This makes it the perfect brace for every day activity as well as for sleeping.