Aquarium Auto Top-Off Kit auto refills and drains water for saltwater and freshwater tank up to 60 gallons. Key Features: 1. Included: 1x ATO Monitor Sensor, • 1x External Sensor, • 1x Water Pump, • 1x 5.9ft Soft Hose, • 1x Hose Holder, • 1x User Manual 2. Auto Top Off system can auto refill and single click to drain aquarium water 3. Put the water pump in the fish tank, and plug the pump cord into the upper (Yellow light hole) to drain the water 4. On the contrary, put the water pump into the reserve water tank plug in the blue light hole for auto refill water, and plug in an external optical sensor to avoid water shortage in the reserve water container 5. Easy to install and use in a fish tank, with no complicated programs 6. When you connect the water pump, the external sensor and power supply begin to monitor and it’s ready to run 7. Suitable for saltwater and freshwater tanks of up to 60 gallons 8. Can be installed in a cabinet filter or directly on the aquarium edge 9. No need to worry about the water shortage in the hidden spare water tank 10. New security technology, two optical sensors monitor the water levels, and double protection can attract your attention quickly 11. If the red light is constantly on, it is working normally; If it is off, it means something is wrong 12. When other lights flash, it indicates an issue with the device; so the top-off kit needs to be checked and corrected regarding the manual • Yellow light: water pump to drain water • Blue light: water pump refills water • Green Light: external optical sensor • Red Light: power adapter 13. Voltage: 220-240V/50Hz 14. Power: 5W 15. Output Voltage: DC12V 16. Flow Rate: 74GP...