WedGees utilize a small wedge of Neoprene positioned behind the ear to secure your eyeglasses. Stops eyeglass slipping instantly. No Straps, no cords, no tubes, For all ages & all eyewear. Relieves temple arm pressure. Secures prescription, safety & sunglasses. Works in hot, cold or humid conditions. Large WedGees are for eyeglasses with 3/8" or greater temple arms.