Check the listing for details. VOOCO CSB10 Ultrasonic Sonic Anti Barking Device. Condition: Used. Listed at 30.88 USD. VOOCO CSB10 Ultrasonic Sonic Anti Barking Device When the Outdoor Bark Control is within range of a barking dog, an internal microphone picks up the sound and the unit is automatically activated. The Outdoor Bark Control emits an ultrasonic sound. The ultrasonic sound can be heard by dogs but is silent to humans. Startled by the high-pitched sound that is safe and effective, the dog should stop barking, as it will associate its bark with this unpleasant noise. When the dog stops barking the ultrasonic sound also stops. The Outdoor Bark Control has 3 range levels and a test mode. It is effective up to 50 feet. The LED: Shows good or Indicate working status. Microphone: Used to detect barking. Sound Activated Speaker: Produces the ultrasonic sound. Switch with 4 Levels of Operation: Off: Used to conserve battery life Test: Used to verify the microphone and speaker are functional 1=Low Range-Up to 15 feet 2=Medium Range-Up to 30 feet 3=High Range-Up to 50 feet