This McKesson Unna boot is made with soft cotton that wraps easily around the leg for comfort.. The material contains a non-hardening zinc oxide paste that applies compression therapy to venous ulcers.. This zinc oxide Unna boot keeps ulcers moist, helping them heal more quickly.. Each roll comes in an easy-to-open vacuum-sealed pouch to preserve moisture.. This nonsterile bandage is single-use and disposable, preventing cross-contamination.. 10.2 centimeters x 9.1 meters.