Deer Whistles Wildlife Warning, Deer Whistle Alert for Vehicles Animal Warning Alarm Ultrasonic Impulse Prevents Deer Collisions Good animal alert whistle system suitable for cars, off-road vehicles, trucks, motorcycles, off-road vehicles, recreational vehicles etc. Save veins, cows, antilops and other animals. This animal sound alarm depend on the wind and do no need battery, it is very convenient. This item designed to give off an unusual but effective sound which can be heard by animals. Small size and light weight whistle system, it is easy to install and carry. Made of high quality ABS, durable and effective to use. size:6*5*3.5cm. weight30g*1. colorblackblack silver. pack*2set (4pcs.