"Logitech USB Unifying Receiver. Product type: USB receiver, Device type: Mouse / Keyboard, Brand compatibility: Logitech. Width: 14 mm, Depth: 6 mm, Height: 15 mm, Weight: 1.23 g. Product colour: Black""Plug it. Forget it. Add to it. The tiny Logitech Unifying receiver stays in your notebook, so theres no need to unplug it when you move around. Connects up to six Unifying devices to your computer so you can easily add a compatible mouse or keyboard – without the hassle of multiple USB receivers. Advanced 2.4 GHz wireless technology provides a powerful, reliable connection up to 33 feet (10 meters) away with virtually no delays or dropouts."