The Penn-Plax Silent-Air Auto On Battery Powered Air Pump is a must have for every fish tank. This battery powered air pump provides a constant supply of oxygen to your fish tank in case of an emergency power outage. The unit has a 3 foot electrical cord that will plug into any standard 2 PIN outlet and will sense when there is an interruption in power. This smart aquarium pump will automatically switch “ON” battery powered pump and provide the much needed oxygen to fish. An extended power outage can be life threatening to most aquatic animal species. Air tubing and an air stone are included (placed in battery compartment of the pump) to make set up easy. This air pump uses 2 “D” batteries (not included) and 220 volts electrical current. The Penn-Plax Silent-Air Auto On Battery Powered Air Pump is safe for both freshwater and marine environments.