Logitech Unifying Receiver for Connecting Multiple Devices
Amazon.com: Logitech Unifying Receiver, 2.4 GHz Wireless Technology, USB Plug Compatible with all Logitech Unifying Devices like Wireless Mouse and Keyboard, PC / Mac / Laptop - Black : Electronics
Logitech Wave Wireless Y-RCP140 Keyboard (No Receiver) Very Clean | eBay