The Gyration AirMouse utilises 'in-air' motion sensing technology. The easiest way to explain is we all know how the Wii works? The Wii uses Gyration motion sensing technology. A tiny gyroscope is housed within the mouse body. The mouse is incredibly accurate on the desk or in the air. No line of site is needed as its radio frequency. So, if you fancy something a little out of the ordinary then this is the best price ive seen it for. The RRP is £69.99 so a real bargain at the moment!