The Pak-Tracker Locator is a distress alarm system designed to help locate individuals at a distance of greater than 900 feet (300 meters) line of sight when they are unable to safely leave immediately dangerous to life and health (IDLH) environments. Unlike ultrasonic or infrared-based tracking systems whose signal can be scattered, deflected or blocked, the 3M Scott Pak-Tracker Locator System operates on the principle of 2.4 GHz RF signal— high-frequency radio waves that effectively penetrate dense smoke and follows doorways and corridors. Fireground tested, the Pak-Tracker Locator is a simple, rugged two-part system consisting of a transmitter and a hand-held receiver. Search and rescue personnel use the 2.2 lb. hand-held receiver to detect the signal of the firefighter’s individually-worn transmitter that is either a personally-worn pocket-sized unit or integrated into a 3M Scott SCBA. The hand-held receiver can monitor and scroll through 36 personal transmitters so as one firefighter is found or removed from the scene, the receiver accepts the transmission of another firefighter.