The CoolerDog Hi-Vis Cooling Collar cools dogs by removing excess heat from around the neck (where veterinarians find cooling to be effective). Made of durable, bright ripstop nylon and 100% Water Flexifreeze® Ice inserts. A border of light reflecting material increases night time safety. Designed with your Dog in mind, CoolerDog Hi-Vis Cooling Collars keep your Dog cool in the heat, and visible to drivers and pedestrians.13-15inch