Cooling Dog Collar. Kool Collar is an extremely effective and unique dog cooling product. The Kool Collar protects your dog from the risk of heat exhaustion or heat stroke. Its patented technology uses ice to stimulate artificial sweat and promote evaporative cooling. Get yours today to keep your pup cool comfortable and safe! Sizing: <b>S</b>: adjustable 11 in. - 17 1/2 in. L <b>M</b>: adjustable 17 1/2 in. - 24 in. L <b>L</b>: adjustable 24 in. - 30 1/2 in. L