SAVING LIVES & PROPERTY: Air moving through the device produces sound/ultrasound wave, gives deer advance warning, they may freeze on the roadside, rather than running across the road into the path of the vehicle. PLEASE NOTE: For better effect, an ultrasonic whistle needs match a sound whistle per vehicle. | UPGRADED VERSION: This is the 7th generation deer whistle that features super tiny body, three-hole construction and two wave frequencies. The set comes with 8 whistles, 4 of them produce sound wave while the others produce ultrasound wave, match sound whistle and ultrasound whistle gives better effect to drive deer away. We packaged a sound whistle and an ultrasound in a transparent bag for customer's convenience. | PREMIUM QUALITY & GREATER STABILITY: The set is made of quality molded ABS plastic that endures extreme outdoor temperature. Features upgraded high-strength acrylic double-sided tape for greater stability, and it will not damage your car paint and can be removed completely with alcohol or citrus-based gum remover etc. | THREE-HOLE CONSTRUCTION & EASY TO HIDE: Features three hole construction and one single mount, this set is easy to hide in grill and replaces three traditional separate deer warning whistles. Each whistle measures: 1.3" in length, 1" in width, 0.5" in height. Applicable for all cars, SUV's, trucks, motorcycles, ATV's and more. The range for the deer whistles is one-quarter mile and only works if the vehicle is traveling at least 35 miles per hour. | EASY INSTALLATION: Just remove the adhesive backing and stick the whistles to the grill, front bumper, rear view mirror, or any flat place of your vehicle. Make sure the bigger ends faces the front, and the deer whistle is level with the horizon. The ideal place is where the most air flow occurs, followed by grill, front bumper. Each order comes with 8 warning device sets.