SAVING LIVES AND PROPERTY: Seven Sparta deer warning devices are friendly for animals. Deer warning can emit ultrasonic automatically day or night at speeds above 35 MPH and will warn deer up to 1/4 mile away. The purpose of the deer whistles is to stop the deer from running in front of your vehicle. | DURABLE & WATERPROOF ADHESION TAPES: We upgraded the normal double-back sticky tape to waterproof adhesive tape which is pretty sturdy, they will stay in place even through a professional car wash. | DOUBLE INSURANCE: This set of whistle contains two ultrasonic whistles and two wind whistles. Usually, one ultrasonic whistle(a whistle with hole in the tail) and one wind whistle(a closed-hole whistle) are mounted on the car at the same time. This double sound frequency system will protect the safety of your vehicles from animal collision. | QUICK& EASY INSTALL AND REMOVE: Just peel off the tape cover and stick the device to your bumper or grille. And the whistles can conveniently be removed from base for wash your car. Two deer warning whistles are recommended per vehicle. | COMPATIBILITY: Compatible with different kinds of vehicles, such as car, motorcycle, truck, SUV, ATV, and so on.