PREMIUM MATERIAL: The dog whistle made of high quality stainless steel, not easy to rust and deform, will not harm your and your dogs health. . PROFESSIONAL DOG WHISTLE: The dog whistle transmits sound through high frequency sound, turn the adjustment lever to adjust to the optimum pitch frequencies. . ADJUSTABLE FREQUENCY: Dog training whistle can produce frequencies in a range of 5.4KHz and 12.8KHz, this kind frequencies nearly can’t be heard by human’s ear, but dog ears can. . EFFECTIVE DOG TRAINING: You can use dog training whistle to teach dogs how to obey and let your dog follow your instructions, such as recalling, sitting, lying down, upwards and other skills. . PACKAGE INCLUDE: Package come with 3 pieces black dog whistles with black lanyard, easy to wear around your neck, It’s a good dog training tool. . Gift