Arma Cool Hydro Boots Black. Keep your horse\\\'s legs cool after exercise or trauma with the Cool Hydro Boots from Arma. Designed with micro-crystals that turn into a cooling gel when soaked in water, the Cool Hydro Boots provide a cold compression which helps to reduce inflammation, bruising or swelling, and cooling the tendons after strenuous exercise. The crystals inside the boot swell into the quilted fabric to help create a soft gel pad that conforms to the shape of the horse\\\'s leg for all-over coverage. Designed to be mess-free and reusable, the Cool Hydro Boots allows the horse to remain mobile and is secured with touch close fastenings.