Ultrasonic Dog Whistle, High-Frequency Dog Whistle, Adjustable Ultrasonic Whistle for Training, Barking, Sit, and Recall, 4 Pieces

Adjustable Frequency - You can adjust the adjustable nut on the dog whistle by turning the screw inwards or outwards while blowing the whistle until you find a frequency your dog responds to. Ultrasonic Transmission - Train your puppy with an ultrasonic whistle. Effective Training - Train your puppy with different commands so your pet follows your instructions, such as remember, sit, come, stop, control barking, stay, and house training. Well-Designed - The dog whistle is made of stainless steel with a rust-resistant coating. This set of 3 is durable and sturdy, small and lightweight, and approximately 8.5 cm long.