Amazon.com: Logitech USB 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 Unifying Receiver Wireless USB Dongle PC K540 Keyboard - Newegg.com
Logitech MK540 Wireless Keyboard And Mouse Black | Techinn