3 Ways to Fix your Logitech k780 Keyboard When it's Not Working
Logitech K780 Multi-Device Wireless Keyboard
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
Amazon.co.jp: Logitech K780 Wireless Keyboard, Bluetooth, Unifying, Wireless Keyboard, Windows, Mac, Chrome, IOS and Android, Authentic Japanese Product : Computers
Connecting a Logitech device to your Unifying Receiver (Windows and Mac) - YouTube