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 Unifying Receiver for Connecting Multiple Devices
How To Pair Logitech Unifying Receiver With Mouse And Keyboard | Logitech | Get Fixed - YouTube
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
Take note if you are a using a Logitech Unifying USB dongle, they are wildly insecure - HardwareZone.com.sg
Logitech's Bolt USB dongle bolsters encryption for its new wireless mice and keyboards - The Verge
Dell KM 714 Keyboard [Used] Compatible with Logitech Unifying Device [Just keyboard without device] - GadgetBazar.pk
How to pair more than one device with a Logitech receiver