Protect yourself from aggressive dogs and animals with ALEKO's Ultrasonic Dog Repeller. This device emits a piercing ultrasonic tone that immediately scare dogs away. This noise is silent and harmless to humans. Use it to repel dogs, deer, raccoons, cats, skunks, possums, rodents, bats and more without snares or toxins. It can also be used to train dogs. This device requires a DC 9 V battery (not included), and comes with a wrist strap attached for easy carrying. This is the perfect tool for keeping pesky pets away while your jogging, walking, or bicycling. Small, light and compact--this can fit in a pocket or worn around the wrist.