Logitech USB Unifying Receiver
A bit of helpful tip before you buy a Logitech keyboard or mouse. Logitech basically have two types of connections for connecting keyboards and mouse. Some of their devices are compatible with something called the "Unifying Receiver" this means that you can connect two devices such as keyboard and mouse to one USB receiver. Other devices do not connect to a unifying receiver and instead connect to something called a nano received. The nano receiver is unique per device so will not connect to another keyboard or mouse from logitech other than the one it came with. So the most popular MK270 combo that Logitech have is not compatible with a unifying receiver so if you damage your receiver, you cannot go out and buy a new receiver for your keyboard or mouse. And vice-versa if you damage your mouse from the combo set of MK270, you cannot just buy a replacement mouse that can connect to same receiver. You will have to buy a new receiver too for your mouse unless one comes with it...