Kool Collar - Large: Black Large Retrievers, All Mastiffs, Rottweilers, Newfoundlands, Large Bulldogs, St. Bernards, Mountain Dogs, and more is adjustable 24" - 30.5" in length and fits most large breed dogs Kool Tubes are not intended for use outdoors, using ice inside the Kool Collar is the best way to thoroughly cool your dog outdoors. Use of the Kool Collar and Kool Tubes in kennels and on puppies have also proven effective for reducing separation anxiety The melting ice runs down the front of the dog and not only offers a comfortable cool sensation, but also more importantly promotes evaporative cooling over the very vascular chest area of the dog