1. Unique Design Ultrasonic Bark StopperUnique design for ultrasonic waves, not harmful to dogs or people. Its sound wave is a gentle but effective deterrent that can make the dog quickly quiet down, attracting your dog's attention and encouraging them to stop barking. Its ultrasonic waves are made for dogs, and the appearance of the design is like an alarm clock. 2. 4 Modes of Ultrasonic AdjustmentThere are 4 modes to adjust the frequency. T test mode, 1 low range up to 15 feet, 2 medium range up to 30 feet, 3 high range up to 50 feet. When the dog barks, the red light flashes to show that the ultrasonic works. The green light flashes after the dog stops barking to wake up. Red light flashes when the battery is low. 3. IPX4 Safe Anti Barking DevicesThe Bark Deterrent is housed in a professional IPX4 waterproof enclosure, can withstand any bad weather and work normally. Its robust design makes it an ideal option for outdoor settings. When barking is detected, the anti barking device emits harmless ultrasonic waves. This bark stopper has a small and lightweight appearance and can be used outdoors when carried. 4. Applicable RangeEffective in controlling excessive barking, ideal for apartments, condominiums or homes with nearby neighbors. It can be placed on the wall, fence or tree. Any indoor or outdoor location is okay. Its sound waves can reach up to 50 FT to control excessive barking of your neighbor's dog or even stray dogs.