Devisys Original - Studded grip device for work and free time! According to a study at VTT (Finnish governmental technical study center) the most common type of slip starts with the heel - the Devisys brings hard metal studs in that most important area! - Sizes S and M: 4 studs (see main image) - Sizes L and XL: 5 studs (see extra image) - Hard metal studs - the kind used in the best studded tires - S: women's narrow heel shoes and children's shoes, sizes: 32 - 36 - M women's winter shoes, sizes: 37 - 39 - L: men's winter and outdoor shoes and wide heel women's shoes, sizes: 40 - 44 - XL: for very wide heels, such as work boots, rubber boots and hiking boots, sizes: 45 - 50 - Reflectors behind heels - Simple hook and loop attachment makes for easy on and off - EEC tested, CE marked personal protection device Grip devices harm several floor materials and can be dangerously slippery on stone and metal surfaces - only use them outdoors and stay aware of different materials. Always tre