Fuel Doctor Holdings, Inc. provides fuel efficiency boosters for motor vehicles primarily in the United States and Canada. It principally offers FD-47, a fuel efficiency booster, which plugs into the lighter socket/power port of a vehicle. The company also provides FD-38 power port splitter that plugs into a single lighter socket for portable cassette players, boom boxes, radar detectors, cell phone chargers, or any other 12-volt accessory used in vehicles; and FD-22 USB car charger adapter for charging personal digital assistants and other USB peripheral devices in a vehicle. Its products under development comprise FD-65, a 12-24-volt fuel efficiency booster for heavy truck rigs; and FD-83 fuel efficiency booster for boats. The company distributes its products to retailers. Fuel Doctor Holdings, Inc. is headquartered in Calabasas, California.