First Alert is a brand of the American security company, based in Aurora, Illinois. They manufacture carbon monoxide detectors, smoke detectors, heat detectors, fire extinguishers and other safety products such as flashlights and ladders for fire evacuation. They support fire safety in partnership with U.S. Safe Kids and the U.S. Fire Administration by providing smoke alarms at a reduced cost to low-income families in the United States.[1]​.

The ONELINK brand of First Alert was called all models before March 3, 2006 and all models with model numbers "SA500" and "SCO500".