[Mini Aquarium Heater] This small aquarium heater is 5cm (1.97 inches) in length, space-saving and easy to hide in the fish tank. The temperature range for the Celsius model is 18C to 34C. Choose the appropriate model based on your requirements. [USB Powered Tank Heater] This heater operates on a 5V/2A USB power supply, providing safe and reliable heating. Eliminates the risk of electric shock to fish. Use a 5V/2A power adapter (not included) or a 5V/2A power bank (not included) to power the device. [Precise Temperature Display] Utilizes smart inverter technology with a built-in chip to maintain a consistent water temperature. Offers more accurate temperature control compared to manual knob settings. The digital display allows for clear and easy temperature reading. [Overheating Protection and Power-off Memory Function] Automatically shuts down if the water temperature exceeds the safe range. The heater retains the previously set temperature and resumes operation at the same setting after power is restored. [Widely Used] Suitable for small aquariums of 1-5 liters. Compatible with both freshwater and saltwater environments. Can also be used in pet fountains and for plant seedling cultivation. Please verify the product specifications to ensure compatibility with your setup. Note: Product design may vary slightly between batches. Minor differences in color or appearance may occur due to manufacturing updates. These variations do not affect performance. Color: Black Material: Plastic Package Contents: 1 x Fish Tank Heater (Other items not included) Note: Lighting and monitor settings may cause slight color variations between the image and the actual item. Measurement tolerance: +/- 1-3 cm.