This dog whistle will help you control your dog's barking easily and effectively. The frequency of this whistle is so high that only dogs can hear it, so you don't have to worry about annoying, high-pitched noises. This dog training whistle is a great tool to promote effective barking control. Professional dog whistle: you can adjust the height to get the right frequencies, loosen the sound adjustment screw while blowing air from the air inlet, turn the adjustment lever to set the optimum height. Once the adjustment lever is turned, tighten the sonic adjustment screw. This dog whistle can be used on any breed of dog. Like all silent whistles, this professional dog whistle makes a little noise. To some it looks like air is escaping, as if you are blowing through a straw. Others have heard a very faint hiss, like when a teapot begins to boil. It's a great way to hear your dog while you train him and teach him obedience. When your dog does it right, give him a reward to taste, approach to make your dog a listener and obedient friend. Anti-lost design: Our dog training whistles come with a lanyard high quality and a special locking nut and cover, it allows you to carry this whistle anywhere without worrying about losing them. Product Name: Pet Whistle. Product material: metal Product size: 0.9 x 8.0 cm. Product weight: 15g/piece Color: Black Quantity delivered: 2 pieces Note: The data is manual measurement, please allow 1-28cm error, due to differences between light and screen, there will be a certain difference in color, the specific received in kind shall prevail.