?Features: 1.Durable weatherproof for indoor outdoor use 2.Use lowintensity ultrasonic, silent to humans, no harmful 3.Use ultrasonic sound to deter unwanted barking, more effective 4.Detects barks up to 33 feet with the waterproof sensitive internal microphone 5.Three levels of operation.Switch with 3 Levels of Operation: Testused to verify the microphone and speaker are functional 1st gear 1530KHZ frequency sweep 2nd gear 20KHZ 3rd gear 2030KHZ frequency hopping and flash ?How It Works? 1. When the outdoor bark control is within range of a barking dog, microphone pick up the sound and unit is automatically activated. 2. The outdoor no bark control emits an ultrasonic sound.(ultrasonic sound can be heard by dogs but is silent to humans) 3. Startled by the highpitched sound, the dog should stop barking, it will associate its bark with this unpleasant noise. 4. When the dog stops barking the ultrasonic sound also stops. ?Specification: Material: Plastic Size: (L) x (W) x (H) 9.7 x 5.6 x 3.3cm / 3.82'' x 2.20'' x 1.30''(appr.) ?Package Includes: 1 x New Bark Control 1 x English Manual 1 x Charging Cable 1 x Lanyard