Boot opening measures approximately 5.25 around PUDDLE PROOF: Constructed with 100% waterproof and crack-resistant PF-1 High Content Anti-Fatigue natural rubber, non-slip soles, slip-resistant tread,?and pull-tabs for easy on-and-off wear. WHAT??S ON THE INSIDE: Cushioned/Contoured Wool-Plus sockliner insoles and internal shank system provide all-day comfort and arch support. The unique long-wearing, high-abrasion lining provides moisture wicking, ensuring your feet stay dry. THE SPECIFICS: Measurements include a 5.25? high shaft, 12? calf circumference, and 1.25? heel; the low shaft offers a more universal fit on most women??s calves.?Our boots run slightly big; it??s recommended to size down if in between sizes. ALL-DAY COMFORT: Not only fashion-forward enough to wear to work or to run errands in the rain, but perfect for gardening, light hiking, or camping to keep mud at bay; designed for your comfort. SEASONLESS APPEAL: Whether you??re out in the pouring rain in Spring or Fall, or you??re dealing with heavy snow when it??s cold, this waterproof, all-season design has you covered when the weather turns.