Protect yourself from dangerous dogs while cycling, walking, jogging, etc. with the sonic animal chaser. It produces a 25 KHz frequency sound that the human ear can not detect yet is extremely discomforting to animals. It is able to repel vicious dogs (can also be used to repel cats, squirrels and other garden pests) without harming them. This animal chaser has an effective range up to 20 feet (about 7 meters) with a prime operating range of 5 to 6 feet. To make sure you are aiming the animal chaser in the best optimal area (around the head/ears), it has a built-in laser sight. It's even safe enough to use for training dogs and cats. Covered under a 90 day warranty. Requires one 9 volt battery that is not included.