Small Aquarium Heater with Temperature Control with Built-in 15W Thermometer Description: SMALL AQUARIUM HEATER: Specially designed for small aquariums with a capacity of less than 1 gallon, does not take up space in the aquarium, USB power supply, rated voltage DC 5 V. INTELLIGENT AND PRECISE CONSTANT TEMPERATURE: USB heating rod, the temperature can be adjusted in the range of 20-34 degrees, when the water temperature is 0,1 lower than the set temperature, enters the temperature control state OVERHEATING PROTECTION: When the water temperature exceeds 36C, the H display and indicator light will turn yellow until the temperature drops below 34C and normal operation resumes. EXTERNAL CONTROLLER: External temperature controller, no need to soak your hands, no need to buy other controllers, easy to install, easy to control. WIDELY USED: Suitable for fighting aquariums, mini aquariums, turtle aquariums, horned frogs, pet drinking water fountain and more. Specification: For tank capacity: 3L Size Chart: Cable length: 140 cm/55,12 inch Heater: 6 cm x 2,5 cm/2,36 inch x 0,98 inch The package includes: 1 aquarium heater