This handheld unit is a humane weapon to train your dog. Designed to fit comfortably into your hand or clip to a belt, Dog Off also features a handy flashlight. TOUCH THE BUTTON, and it will transmit a burst of ultrasonic sound (not audible to humans) to help train your dogs behavior. HOLD DOWN THE BUTTON and trigger a stronger high-pitched ultrasonic siren (not audible to humans) that may help repel unfriendly dogs.The sound is irritating to dogs, but is completely safe and humane Pull the personal alarm switch to set off a loud audible alert that will alert others.Requires one 9 volt battery, two year manufacturer warranty.