Helpful tool: air moving through the deer whistle will produce sound/ ultrasound, this kind of sound can alert deer, elk, moose, antelope and kangaroos approaching vehicles, which effectively avoid deer and vehicle collisions Safe for you and your pet: the deer warning device is equipped with 10 whistles, 5 of them produce sound waves, the others produce ultrasound; However, people and pets (such as dogs, cats) in the car can't hear it, so there's no damage to your ears or health East to install and remove: just remove the adhesive backing and apply the whistles to the grill, front bumper, rear view mirror, or any flat place of your vehicle; Make sure the bigger ends are facing the front, and the deer whistle is level with the horizon; The ideal place is where the air flows most, followed by grill, front bumper, they can be easily removed from the base when car washing is needed Safe accessory for driver: the deer warning device is a necessary car accessory for driver who live in a wild area; The whistle produces ultrasonic frequencies and make warning sound, thereby reducing vehicle collisions International products have separate terms, are sold from abroad and may differ from local products, including fit, age ratings, and language of product, labeling or instructions.