Automatic Dog Bark Control The device intelligently captures barking dogs from up to 15 meters away, and automatically emits ultrasonic sound that distracts your dog to stop unwanted barking, so you can enjoy 'a moment of peace and silence. Dog Bark Stopper Ultrasonic frequencies are harmless to pets and completely inaudible to the human ear. If the dog is hard of hearing or aggressive, the device may not work as expected. It is not recommended to use one device against two or more dogs barking at the same time. 3 Levels of Operation Adjustable frequency dog bark deterrent is suitable for different dogs. 15KHZ-30KHZ is suitable for big bad dogs. 20KHZ Suitable for gentle dogs. 30KHZ Suitable for small dogs. It is recommended for dogs aged 6 months to 8 years. Rechargeable by USB Ultrasonic dog repellent incorporates a rechargeable lithium battery, the device can work continuously for 30 days after have been fully charged within 5 hours. Red / blue color indicates battery status. Easy and Waterproof Installation Dog bark stop device can be hung on tree, wall or fence to prevent your own dog or your neighbors' barking. Make sure the bark controller is facing the dog within reach without any obstruction. Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours Hope you have a pleasant shopping experience!