This patented device quickly and humanely restores peace and quiet to a home by helping to curtail a dog's incessant nuisance barking. No special collar is required; when a dog barks within 25' of the unit in an open space, it emits a harmless ultrasonic tone (inaudible to humans) that startles the animal into silence. After several weeks of use, the dog begins to associate its nuisance barking with the unpleasant sound, which conditions him to curb the undesirable behavior. The device works on all breeds and sizes and is most effective when used in conjunction with standard canine obedience training techniques. The unit can also be activated manually to help you correct a dog's other bad habits, such as lying on furniture or foraging through the trash. Requires one 9-volt battery that provides power for two months; an LED indicates battery life. For indoor use only. 3" H x 5" W x 2 1/2" D. (8 oz.)