JBL DigiScan Alarm is an aquarium thermometer with a large digital display for displaying the water temperature in the aqaurium. The Themometer is mounted on the outside of the glass and displays the temperature in the aqaurium very accurately and easily legible. Two preset alarm points are displayed when reached (display flashes).JBL Aquarium Thermometer DigiScan Alarm+ digital aquarium thermometer that displays water temperatures from 0-37C in 0.1C increments+ preset alarm flashes below18 and from28C+ attachment: Insert the battery, remove the protective foil and simply stick the thermometer onto the outside of the aquarium pane+ the 4-part velcro sticker makes it easy to remove the thermometer at any time+ accuracy: 1.0C+ battery: 1 x AG10+ dimensions: 5 x 3.5 cm+ digit height: 1.8 cm - easy to read+ DO NOT immerse the thermometer in the water!+ the water temperature is very precisely forwarded through the aquarium pane to the temperature contact on the back of the therm