Aquarium Thermometer (1) Easy to use. To stick the thermometers on the aquarium or pet house, you can monitor if the temperature is suitable for your pet. (2) No mercury, non-toxic, safe for your pet and environment. (3) No batteries required, Unbreakable and Reusable. (4) Logo and advertisement printing allowed, can be produced in any color, design and shape. (5) Perfect promotion gifts, create a powerful brand reminder to your clients.