MuchBuy Auto Anti Dog Barking Tone Shock Training Collar for Small Medium 5-150 Pound Dogs This device is for training the dog to stop nuisance barking when you're annoyed by the dog's barking It can auto turn on/off and increase level of tone and shock of your dog when he/she persist barking When your dog is quiet for 30 seconds or more, the collar resets to the mildest correction level After experiencing several times, your pet dog will learn to keep quiet at at mild sound level Voice Recognition feature minimizes false triggering. Extremely small and light weight, adjustable belt length, maximum up to approx. 1.6ft