Adjustable Sound Pet Dog Training Ultrasonic Whistle Key Chain Teach your puppy to be on their best behaviour with this essential dog training whistle Material: Chrome Plated Brass Color: Chrome Silver, Length: 5.5cm (approx.) 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 Package include: 2 * pet training whistle(Key ring loop included)