Dog Whistle to Stop Barking with Adjustable Special 2-Tone Frequency from PetVitalix for Obedience, Repellent Effect and Clicker Teaching with Keychain, Necklace, Anti Lost Pet ID Tag, Training Ebooks UNIQUE 2-TONE FREQUENCY: Your dog will hear a combination of (1) silent ultrasonic sounds and (2) audible tones. Get his/her attention to listen to your new whistle orders. INDIVIDUALLY TUNABLE - Easy adjustable to multiple frequencies to train your dog all commands like sit, come, stay or stop barking. FAR REACHING - Works great for calling dogs from far away! Get your dog's attention right away without straining your vocal voice and drawing attention to yourself by jumping around like a maniac. NEW ANTI LOSS FIXING CAP - Never lose your dog whistle again with our special snap on cover. SMALL AND LIGHTWEIGHT - Only 2 inches long and 0.4 ounces, perfectly to hang on your key ring to have it by your side all time or use it with our included lanyard.