The Penn-Plax Air Pod AC/DC Pump is a must have for every fish tank. This air pump provides a constant supply of oxygen to your fish tank and automatically turns to battery backup in case of an emergency power outage. The unit has an electrical cord that will plug into any standard outlet and will sense when there is an interruption in power. This smart aquarium pump will automatically switch to battery backup and provide the much needed oxygen to fish. An extended power outage can be life threatening to most aquatic animal species. The air pump has dual air outlets with adjustable air flow allow for customization according to your aquarium's needs. A handy power indicator light allows you to easily see which power source is being utilized and air tubing is included to make set up easy. Aquarium air pump uses 4 D batteries which are not included and 110 volt electrical current. The Penn-Plax Air Pod Aquarium Air Pump is safe for both freshwater and marine environments up to 55 gal.