Material: Made Of Sturdy Abs Plastic, Resistant To High Outdoor Temperatures And Sub-Zero Temperatures. Ultrasound Cannot Be Heard By Humans Or Pets In The Car. Package: 4 Deer Whistles. Each Deer Whistle Comes With Double Sided Tape. Each Package Contains 2 Open Ultrasonic Models And 2 Closed Wind Models. Feature: The Car Bumper Deer Whistle Works When The Car Is Moving Over 35 Mph. The Whistle Emits A Sound Which Can Alert The Deer, Prevent The Deer Or Other Wildlife From Colliding With The Car. Easy To Install And Remove: Peel Off The Adhesive Tape Cover And Stick The Device On Your Grill Or On Top Of The Hood. Clean Vehicles Before Application. Can Also Be Easily Removed From The Base For Cleaning. Compatibility: Compatible With All Cars, Such As Motorcycles, Suv Trucks, Atvs, Etc. Could Save Many Lives