describe:Bark Control Whistle - Dog Training Deterrent Whistle.Features: t Adjustable pitch Simply tighten or loosen a screw to exercise your dog's frequency t It should be noted that this whistle can be heard by the human ear, which is essential to gauge its efficiency t Use dogs with different sequences whistle to train your dog. For example, a long burst might mean coming, while a series of short intermittent bursts might mean sitting and keeping your whistle commands consistent, your dog will always know what you expect from him Behaviors that require training, such as whistling during meals before they get food, it only takes a few times for your dog to respond quicklySpecification:- 100% brand new- suitable for all dogs- Easy to play - High-pitched dog whistle- Highest pitch in Acme Dog Whistle Class- No cork balls, so it produces a solid tone- Dimensions: 7cm x 0.7cm