The 4 PCS Deer Whistles for Car are essential for avoiding collisions with deer while driving. These black whistles come in a set of four and are designed to save deer by warning them of approaching vehicles. With dimensions of 3.9 x 3.11 x 0.87 inches and a weight of 1.76 ounces, these whistles are compact and lightweight, making them convenient to use on the road. With a customer review rating of 4.0 out of 5 stars, these deer whistles are a reliable and effective tool for promoting safe driving in areas with deer populations.