Pet Dog Anti-barking Vibration Anti-barking Collar USB Rechargeable: No batteries required, just plug in via USB to charge, very convenient. Ultrasonic technology: The collar emits ultrasonic waves that are inaudible to humans but can effectively stop barking. Automatic Collar: The collar automatically activates when barking is detected, making it easy to use and effective in training your dog. Vibration function: The collar also has a vibration function, which can be used as an alternative to ultrasound. It is an effective behavior modification tool that can help you train your dog to bark less. Easily recharges with a USB cord It's smaller, lighter and more comfortable for dogs. Whether your dog is small or large, our adjustable dog bark collar will fit them well. The collar is waterproof, so you don't have to worry about using it even on rainy days. For some larger dogs with longer hair, it is recommended to cut off some hair to ensure product efficiency. Please make sure you have a good battery before testing. Do not put on your dog while he or she is sleeping, lying down or unattended. Make sure the probe is one finger's width away from the dog's neck (test by inserting your finger between the dog's neck and the probe) Colour:Blue Material:ABS+nylon Package Contents: 1 * Bark stopper Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.