Our patent pending Pet Therapy line is customized and patented for canine anatomy. We've modified the gel formula in our pet line for prolonged effectiveness. All Caldera reusable Pet Therapy Gel is Made in the USA and can be applied either hot or cold. Pet Therapy Gel is latex free, non-toxic, non-hazardous, microwave and freezer safe and remains pliable when frozen. Heating and freezing instructions are on each gel pack. Ideal for Use with Pet Therapy Wraps Each patent pending Pet Therapy Gel Pack has been specifically designed to work in conjunction with a coordinated Pet Therapy Wrap. Gel Pack Sizes Medium Short Stifle = 5½" x 5¼" x ½" Medium Shoulder & Hip = 6¾" x 5" x ½" Medium Tall Stifle = 7½" x 6½" x ½" Medium Universal = 6¼" x 4" x ½"