Two 39-inch long independent probes and sensors allow for monitoring of heat and humidity at different locations. Use in terrariums, incubators or other pet animal applications. Easily switch between Fahrenheit or Celcius. Waterproof temperature probe can be used in air or submerged in water. (Humidity probe not waterproof, do not submerge in water.) One LR44 1.5v battery and mounting suction cups included