True’s salad/sandwich units are designed with enduring quality that protects your long term investment. Factory engineered, self-contained, capillary tube system using environmentally friendly R290 hydro carbon refrigerant that has zero (0) ozone depletion potential (ODP), & three (3) global warming potential (GWP). Patented forced-air design holds 33°F to 41°F (.5°C to 5°C) product temperature in food pans and cabinet interior.