Polar-Pak Walk-In Coolers and Freezers are manufactured by Kolplak. This series of Polar-Pak Walk-in Coolers and Freezers include a Self-Contained Refrigeration Package that can be located on the top or sides. This refrigeration system does not need a drain for it has its own self evaporating system. The Polar-Pak Walk-ins are very easy to install. They are for indoor installations and not for outdoor use.