Temperature is critical to maintaining a successful terrarium or aquarium. With ESU Reptile's Digital Thermometer, you can be sure your pet fish or iguana's home is at the ideal temperature to keep them active, happy, and healthy. Small and lightweight (dimensions 2.25L x 1.38H x 0.50W, weight 1.6 oz), this battery operated thermometer is easy to mount, use, and read. Ideal for aquariums and terrariums with readings in Fahrenheit or Celsius to 0.1 degree. Includes mounting suction cups, battery, and 39" long temperature probe.