The Thermocouple Solid SImulator does not measure the air, it takes on refrigeration temperature as food does and further supports your food safety program. Made of FDA compliant material it simulates food product temperature in changing ambient conditions of any refrigerator, freezer, walk-in or delivery truck. The temperature of the Solid Simulator will display immediately when plugged into any Type K Thermocouple Instrument. Walk In...And Plug In!