PetGeniuses Two Pack of UltraSonic Dog Training Whistles - Ultimate Whistle to Stop Barking - Dog Whistles with Adjustable Frequencies to Change Sound and Pitch HELP YOUR DOG OR OTHERS TO STOP BARKING ? Distract your dog from their barking spree and distract them from whatever is causing the barking or other unwanted behavior ? Dog whistles are a perfect training tool to teach keep quiet ? Professional dog trainers agree it's still the most effective way of communicating with their dogs. TWO-PACK OF WHISTLES SO YOU ALWAYS HAVE ONE HANDY ? Why only get one dog whistle when you can get two for the price of one? TRAIN YOUR DOG THE RIGHT WAY ? Dog Whistles have been used over a 100 years, still the most effective tool for training ? Use the dog whistle with changing orders ? 100% LIFETIME MONEY-BACK GUARANTEE ? You heard that right! ? No questions asked, 100% lifetime, money-back guarantee on these dog whistles! PET GENIUSES ULTRASONIC DOG WHISTLES ARE THE BEST DOG WHISTLES ? Emits frequency that your dog can hear from far distances to recall ? Just adjust the pitch and blow the whistle to your dog ? Wait until he is asleep and gently blow on the whistle ? Continue to test the whistle until your dogs ears perk up, your dog whistle has a nut and screw that you can adjust and lock the frequency.