Ultra Paws Rugged Dog Boot Measure width of paw for best fit (see photo/video instructions). The paw must be smaller than the boot size: Small 2 1/4"; Medium 2 3/4"; Large 3 1/4"; XLarge 4. (If in between sizes, add a Doggie Sock). This is the boot for hunters, urban settings on asphalt or concrete, snow, and protection from salt in the winter. Easy to put on - difficult to slip off, two Velcro straps with slides fasten the boots. Tough, water resistant 1000 denier nylon material with the top of the toe wrapped, sole is flexible, skid-resistant, recycled tire material. The sole performs in wet and dry, hot and cold conditions and its recycled tire sole is suited for tougher conditions.