If you worry about how your fish will survive in the event of a power outage, the Silent Air B-11 Air Pump will give you peace of mind. It runs on 2 "D" batteries (not included) and plugs into a standard AC outlet; it detects a power outage immediately and begins to provide lifesaving bubbles for as long as they're needed. When the power comes back on, it shuts off to preserve battery life. Built-in on-off switch. Can be unplugged from wall and used as a portable pump. Includes 18" of airline tubing and 1 airstone.