Use indoor: Just fill the collar with the KoolTube that it comes with (also sold seperatly). The Kooltubes are store between use in the freezer, to keep them ready for use. KoolTubes are intended to be used anytime it is not practical to have your dog dripping water from using ice in the KoolCollar. The KoolTubes are a semi-disposable, non-toxic, and non-staining alternative to ice. It is perfect for use inside the house, traveling in a motor home, car, truck, etc.
Each KoolTube usually lasts about 30-50 minutes depending on the ambient temperature and the dog's activity level.