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 MK520 Complete Wireless Combo K520 Keyboard and M510 Mouse USB Unifying (920-008972) (Renewed) (920-008972-cr) - Newegg.com
Logitech MK520 Wireless Keyboard Mouse Combo with Unifying