Logitech Unifying Receiver for Connecting Multiple Devices
Logitech Unifying USB Receiver for Wireless Mouse and Keyboard, 6-Device (910-005235) | Staples
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 MK540 Advanced Wireless Mouse and Keyboard 920-008671
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
Why you should really, really update your Logitech wireless dongle - The Verge
Logitech Mk540 Wireless Keyboard Mouse Combos With Unifying Usb Receiver Mice Keys Set For Pc Laptop Office Business Game - Keyboard Mouse Combos - AliExpress
Logitech K540 Wireless Keyboard With Unifying Receiver Very Good 5465 | eBay