Traction devices for walking and running. Pro tip: it's often easier to mount them on your shoes before putting your shoes on. - Exchangeable tungsten carbide studs, 6 pieces per foot - Choose the size according to thies size table when using with running shoes, and size up one letter size if using with mid high shoes: - Size S 35-38 - Size M 38-41 - Size L 41-44 - Size XL 44-47 - Body made of natural rubber Do not use indoors. The devices can be very slippery on smooth stone and metal surfaces, and can damage softer flooring materials. CE certified: (EU)2016/425