The patented design ensures it will only be activated by a specific dog’s bark so other dogs in the neighborhood won’t trigger it. This is the smallest spray collar on the market today making it lightweight and comfortable. Collar has adjustable buckle closure to fit necks up to 28” and low-spray indicator. Runs on a 6V alkaline battery (not included). Includes a refill bottle that emits 40 sprays. Additional refill bottles are available (see item ZT097).