Make sure your refrigerator and freezer are maintaining the optimum temperature for food safety. Solid bi-metal construction. Versatile design stands or hangs on refrigerator or freezer shelf. Easy-to-read, large dial reads in both Fahrenheit and Celsius. The registered NSF® Certification mark on food equipment products confirms that NSF® has certified its conformity with the relevant NSF® / ANSI standard for components and use.