Esky Medium Large Anti Back No Barking Dog Training Shock Collar, for 30-150 pounds Dog Small size and light weight. This is the newest anti-bark collar with the most intelligent system Controlled by a microprocessor which distinguishes your dog's bark from other environmental noises and automatically delivers ultrasonic and/or static shock after each bark The collar can effectively and humanely stops barking when it is worn on dogs An adjustable collar strap is suitable for most small and medium dogs Low battery consumption