Dog Whistle - Silent Ultrasonic Professional - Premium Training Whistle - Controls Barking, Training Aid - Stop dog barking - Adjustable Pitch - Small and Lightweight, Pocket Sized Our silent dog whistle is a repellent aid, to train your dog or your neighbor's dog to stop barking. With diligence, you can train in as little as a few days. Small & very lightweight, only 2" long and weighs .4 oz. Our convenient design is the best for portability.You can carry your ultrasonic dog whistle anywhere you take your dog. You can use this long range whistle keychain not only as a bark aid, but also for basic commands like site, stay, come. See below for training tips and examples. Our whistles are the safest form of training. No hurting or shocking needed. Great for deaf dogs. Unlike others, our whistles have adjustable frequencies and pitch so you can find the most effective sound and control for your dog.