Designed to protect both the vehicle's occupants and local wildlife, the GWS Hopper Stopper is a brilliant device used both here in Australia and overseas. Once fitted to a vehicle, at speeds above 55kph, the GWS Hopper Stopper units begin to emit a whistle, which increases in frequency as speed increases until it can no longer be heard by a human. This high-pitched frequency can still be heard by animals however, and thus can serve as a warning device notifying them of your vehicles approach. According to the manufacturer "this product has an 80% protection rate against accidental damage caused by animal vehicle contact" greatly reducing the risks associated with country driving where wildlife may be more prevalent. Over 300,000 of these products have been sold in Australia, so don't get left behind! If you're concerned about wildlife and the safety of your vehicle occupants, invest in a GWS Hopper Stopper.