【Bark Box】Our Bark Suppressor Is Designed To Effectively Suppress Anti Barking Devices And Help You Maintain A Quiet And Peaceful Environment In Your Home. Utilizing The Latest Ultrasonic Technology, The Bark Control Device Will Automatically Emit A High Pitched, Variable Frequency That Can Only Be Heard By Dogs And Will Not Be Picked Up By Humans, But Is Effective For Dogs. Dog Whistle Stop Barker Has No Shock, No Vibration, No Noise, Won'T Touch The Dog'S Skin, Won'T Affect The Dog'S Hearing, And Is Harmless To The Dog. Suitable For Small, Medium And Large Dogs.