Logitech USB Dongle Extender - Works with Unifying Receiver. 1 x USB Dongle Extender. Varies the position of the USB receiver and reduces the possibility of interference. Makes your computer's USB ports more easily accessible.
I lost my dongle while traveling around the state working at various locations. Buying a new keyboard was going to cost over $80. This dongle saved me quite a bit of money and paired easily to my keyboard.