The Rucanor Only Bandage from 3 mm neoprene with terry lining for extra comfort. The bandage is just a sanitized Unique treatment for no fragrances and no bacteria. To get the right size, you can outline in inches from your ankle measurements. It should measure the circumference of the outer knob and the inner protuberance of the ankle. S=15 - 20 cm, M=20 - 25.5 cm, L=25.5 - 30.5 cm, XL=30.5 - 35 cm