High-Quality Reptile Tank Thermometer Hygrometer with External Probe: Precise supervision of the temperature and air humidity in reptile tanks, terrariums and vivariums. (Note that the temperature does not appear on the screen until the external probe is plugged in.) Alarm Function: High/Low Temperature Alarm Function for 10 seconds. The default setting is high 28, low 18; you can set the high and low alarm temperature range arbitrarily. The alarm function can more effectively remind you to notice temperature changes in your pet's living environment. Fahrenheit Celsius Convertible: Temperature can be display in Fahrenheit or Celsius by press the C/F hole on the back of the item with a paper clip. Stylish Design: Stylish looking digital vivarum thermometer with hook and loop for easy to install to any reptile tanks, fish tanks or terrariums. Fantastic Value: This accurate reptile thermometer and hygrometer allows you to monitor the temperature and humidity in the reptile tanks at all times to makesure your beloved reptiles are in perfect health. Also Excellent As An Aquarium Thermometer: Put the waterproof external probe in the aquarium to observe the change of water temperature. Quality Guaranteed: Our carefully sourced range of thermometer hygrometers are manufactured to the highest of standards our customers expect.