It's like an extra set of eyes, perfect for getting the early warning that your prey approaches! The Kit comes set with a receiver unit and 2 sensor units to mount wherever you want. It's the perfect system if you're trying to drive a buck to a specific hunter, the receiver will notify you that an animal is inbound, letting you set up to take the best shot possible. And it's not just for hunting! Great for monitoring around your home for unexpected people or animals. However you use it, you'll get the early jump! Each sensor comes with mounting strap for easy re-positioning, Mossy Oak camouflage pattern on the sensor units keep them undetected, Receiver supports up to 6 sensors, Base unit requires 4 AA batteries (not included). Sensors require 2 AAA batteries each (not included).