We highly recommend this pump because even if the power goes out, this compact workhorse will continue to supply oxygen to your aquarium. It runs continuously on 110V, switching automatically to battery during power loss, then recharges when power is restored. Features two modes: High runs 10 hours continuously on full battery and low runs 20 hours intermittently, 50 seconds on and 50 seconds off. 6V rechargeable battery included. Two 3/16" outlets provide a total of 0.15 cfm of air at 30" of water depth for two airstones. Rated at an output of 240 liters per hour. For aquariums up to 80 gallons. Open center cover and attach red wire to start. Measures 9-1/4" x 6-1/4" x 3-1/4".

Operating Instructions:

1. Select the suitable length of flexible aquarium airline tubing and connect one end to the airstone and the other to the Battery Backup Pump outlet. Place the airstone in desired location in aquarium. Note: Make sure to place the pump in a location above the aquarium water level to prevent possible back siphon.
2. Switch to HI or LO position. When in HI position, the air pump will run continuously during a power outage. In LO position, the pump will run intermittently, in 50-second intervals.

NOTE: In order to extend service life of the rechargeable battery, unplug A/C power once a month and discharge for 30 minutes.