STEELMAN 06610 Replacement Control Unit for ChassisEAR Electronic Squeak and Rattle Finder REPLACEMENT UNIT ONLY - Replacement main control unit for the STEELMAN 06600 ChassisEAR Electronic Squeak and Rattle Finder PINPOINT TROUBLING NOISES - Easily pinpoint troubling noises that cannot be duplicated in a repair stall and only occur during road driving MULTI-CHANNEL - Connect up to six (6) microphones to different under-chassis locations simultaneously to find a noise's source INTUITIVE CONTROLS - Two intuitive dials control microphone volume and channel selection with a bright red LED power indicator COLOR CODED LEADS - Each microphone / clamp is color coded for easy identification and channel selection BATTERY OPERATED - Powered by a single 9V battery (not included)