Super Mini Fish Tank Heater USB Powered 10W Adjustable Mini Submersible Aquarium Heating Rod with LED Display Thermostat EU Plug 100‑240V Item Type: Mini Aquarium Heater Material: Quartz Tube, Plastic Use: Fish Tank Mini Heating Rod Adjustable Range:  Celsius: 15‑34℃ Fahrenheit: 59‑9℉ Applicable Water Volume: Below 3L Power: 10W Over temperature protection technology: when the water temperature is lower than the set temperature 0.1 ℃ into the temperature control state, the water temperature exceeds 36 ℃ display HH, the indicator light is on yellow, until the temperature back to 34 ℃ or less, resume normal work. When the heating rod is working, the red light is on, when the heating rod leaves the water surface, the LED screen will show L1 and keep flashing to remind, while the heating rod will power off and stop heating.