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 - Wikipedia
Logitech K400 Plus Touchpad Keyboard for TV connected PC
Logitech K400 Usb Unifying Receiver - Wireless Dongle Receiver Usb Adapter 6 M905 - Aliexpress
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
keyboard - How To Replace Logitech Wireless Unified USB Plug In Ubuntu - Ask Ubuntu