USB Small Aquarium Heater Heating Tool Outdoor Temperature Controller 15W 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. OVERHEATING PROTECTION: When the water temperature exceeds 36C, the HH 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/4L Size Chart: Cable length: 128 cm/50.39 inch Heater: 5.2 cm x 2 cm/2.05 inch x 0.79 inch The package includes: 1 aquarium heater