Ozoffer 2x Pet Dog Puppy Training Obedience Whistle Ultrasonic Supersonic Adjustable Pitch

Features
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 gradually know what you expect from him.
The dog's behaviors based on your instructions need to be trained for a certain amount of times. For example, at mealtime, blow on the whistle before they get the food. Repeat doing this and your dog will react quickly.
Specifications
Color: Silver
Weight: 12g
Material: Brass
Length: 53mm (approx.)
Key ring loop included
The dog whistle sound includes 2 parts:
   
Part 1: the Ultrasonic. Human's ear cannot hear it, but dogs can hear it.

Part 2: These light sound can be heard by human, which help owner sound a long or short whistle to train them.
Adjustable pitch, simply tighten or loosen the screw to work out your dog’s frequency. It should be noted that this whistle is audible to the human ear, essential for gauging its efficiency.

Package
2x Dog Training Whistle