Features: Adjustable pitch, simply tighten or loosen the screw to work out your dogs frequency It should be noted that this whistle is audible to the human ear, essential for gauging its efficiency This Dog Training Whistle is designed for dog training, the frequency produced isn't of effect on person, but very useful for dogs, it will sit up, come here, eat, sit down etc. Great for recall over long distances Key ring loop is included Some tips to use the dog whistle: Adjust the pitch & blow the whistle to your dog. Even dogs can't hear all frequencies. Wait until he is asleep and gently blow on the whistle. Your whistle has a nut and screw that adjust the frequency when turned. Continue testing until your dog perks up. You will then know you have reached a frequency he can hear. Use the dog whistle with varying sequences to train your dog. For example, one long burst can mean 'come,' while a series of short, staccato bursts might mean 'sit.' Keep your whistle commands consistent and your dog will always know what you expect of him The dog's behavior according to your instruction need to be trained. Such as, at meal time, blow on the whistle before they get the food. It will only take a few times of doing this and your dog will react quickly. Specifications: Material: Alluminum Color: Silver Length: 5.5cm Hole Diameter: 0.5cm Quantity: 1 Pc Note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-3cm error due to manual measurement. pls make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! No Retail Package Package Contents: 1 Pc x Whistle Flute