This small unit uses vibration and sound to ensure only your dog's barking is detected. As the dog barks it will receive a safe but annoying static correction. When used correctly the bark collar reduces, and in most cases eliminates, the number of nuisance barks. Your dog will quickly learn association and stop the unwanted behavior. For dogs up to 55 lb. 10 levels of light-touch correction. Automatically adjusts to your dog's temperment. Durable, waterproof receiver collar. Good/low-battery indicator. Collar color: Black. Refer to model No. RFA-188 (SKU 806809) for replacement battery.