The First Alert and USI brand understand the importance of securing the ultimate in peace of mind when it comes to safeguarding your home from a collection of internal threats. First Alert and USI have taken the basic premise of a smoke detector and have expanded upon it greatly in the efforts of protecting you and your family from any harm. Combination Smoke Alarms are also available and feature multiple alarm functions in one unit. Detecting smoke and carbon monoxide, an alarm will alert the residence upon any registered threats. First Alert's Ten Year Series and USI's (IoPhic) collection utilize various technologies to achieve optimal results.