MO Advance No Bark Collar - No Harm Shock Dog Control - 7 Sensitivity Adjustable Control Levels For Training Small or Medium Dogs 15-120lbs - Bonus FREE Training Ebook & Extra Batteries A SAFE, HUMANE, AND EASY WAY TO BREAK a dog's habit of excessive barking. Suitable for small to large dogs (15 lbs. and above). SEVEN LEVELS OF SOUND-SENSITIVITY (set via the "+ / -" buttons on the collar), so you can set it to suit the loudness of your dog's bark. Youll also get a Free Bonus eBook Training You Dog The first steps of dog training. THE CORRECTION STIMULUS GOES THROUGH SEVEN STAGES, starting with a short warning sound and progressing to a louder sound plus a mild, harmless shock. After the seventh level, there's no further stimulus for 1 minute to avoid over-correction. LIGHT WEIGHT AND COMPACT, and uses a replaceable battery.(you also get a second battery as a gift. The collar is triggered by sensing sound and vibration at the dog's neck to avoid false triggering from outside noises. This MO brand product is sold with a full money-back guarantee. If you're dissatisfied with your purchase for any reason, contact us for a 100% refund.