The Chattanooga ColPaC Chilling Unit's large capacity and steady chilling means that you or your patients will never have to wait for a cold pack. This unit has a drain valve for easy cleaning and defrosting and is made of sturdy stainless steel, welded construction. Only the Medium (C-5) model is available at this time. The C-5 Model has closed-cell foam insulation and a heavy-duty compressor.