PetSafe PBC-1000 Indoor Bark Control Ultrasonic Pet Dog Training SystemFOR DOGS OF ANY SIZE uses high frequency sound that works to reduce excessive bark of dogs within hearing range; for dogs 6 months and older UP TO 25 FOOT RANGE VERSATILE you can use either freestanding or hand held. Microphone detects barking to prevent false corrections TWO SETTINGS you can set the unit to automatically emit the ultrasonic tone when your dog barks or press the manual button to correct inappropriate behavior NO BARK GUARANTEE Some