LIFEDETECTORTM COMPACT SYSTEM Delsar Search and Rescue Equipment: Detects signs of life during rescue through sensors that can pick up extremely small vibrations transmitted in solid or gaseous media. Seismic/acoustic omnidirectional sensors, position insensitive one to 3,000 Hz. Users may listen to up to six sensors at once and have a simultaneous amplitude display of any two sensors. A small intercom probe (microphone/speaker) detects airborne sounds in voids. The system operates on alkaline batteries and is compatible with older LifeDetector systems. (800) 848-1064.