The features of Allenker dog bark collar * Automatic no bark collar: Independent adjustable vibration and harmless shock modes with 4 levels of intensity (0/L/M/H) and preset beep mode,three levels of sensitivity(L/M/H) .Set to the correct mode to teach your dog no barking * Safe anti bark collar:the shock mode is safety and harmless,you can also set grade 0 of the shock mode to disable shock if you don't wanna to shock your dog. * Humane technology prevents over stimulation: The bark collar will enter into sleep mode if it is triggered 7 times in 1 minute and will be reactive after 1-minute of sleeping time. * No bark collar for small dogs/ medium/ large dogs with adjustable belt for neck circumference between approximately 6.5” to 24” * Anti error trigger dog bark collar: it won't be triggered by the surrounding dog’s barking.