ExpAquaMiracle Adjustable 10W Betta Heater Small Aquarium Heater @ Amazon

SUPER MINI SIZE – This small aquarium heater is “thumb size” - only 1.97” (5cm) in length. Great for nano tanks / betta tanks. The innovative super mini size perfectly solves the headache of the fish keepers on the traditional heaters! Takes up less space, easy to hide, but in full power! Temperature range is 64-93F, for up to 1 Gallon tanks.

5V/2A USB POWER SUPPLY – This 5V/2A USB power supply is very safe. You are away from the worry of electric shock to your beloved fish! Use a 5V/2A power adapter, or a 5V/2A power bank to supply power to the heater. (Power adapter or power bank is not included)

ACCURATE TEMPERATURE – Thanks to the intelligent inverter technology, with the in-built chips this thermostat keeps the heater at a constant temperature at an accuracy of 1F, much more accurate than the traditional knob-controlled heaters. The thermostat shows 2 readings – the current temperature and the set temperature – very easy to operate.

OVERHEATING PROTECTION – Full consideration of safety. This fish tank heater will stop working when the water temperature exceeds 97F. You are free from “cooking fish”! MEMORY FUNCTION – The last setting is stored in the thermostat. In case of a power cut, when the power recovers the heater will follow the last setting.

MULTIPLE USES – This heater can be used for both fresh and marine water. It can be not only used as an aquarium heater, but can also work for turtles, pet fountains, and plant seedling.