PetSafe Outdoor Ultrasonic Dog Bark Deterrent, Weatherproof, Acre Coverage, Anti-Bark

Tone emits in a 180-degree range in front of the unit and reaches up to 50 feet; add more units for bigger yards Easily hang from a tree or rest on a solid surface outside Weatherproof against the rain, snow and sunshine in your back yard Affects all dogs within range, so not best for multi-dog homes LED low-battery indicator to keep you informed; uses a replaceable 9-volt alkaline battery (not included) For dogs of any size; not for puppies under 6 months old or dogs who are deaf or hearing impaired Measures 4 1/2 in W x 7 in H x 3 5/8 in D