Logitech K400 Plus did not come with a USB dongle? Wait!! It's hidden in the box!! | THINKBOX
Logitech Keyboard QWERTY Wireless K400 Plus | Back Market
For Logitech K800,K750,K710,K700,K520,K400,360 Unifying USB Dongle/Receiver 713929760527 | eBay
6 Channel Wireless Dongle Receiver USB Adapter For Logitech Mouse Keyboard K400 | eBay
Wireless Dongle Receiver Unifying USB Adapter For Logitech Mouse Keyboard Connect 6 Device For MX M905 M510 M505 Keyboard K400
Logitech Wireless Touch Keyboard K400 with Built-In Multi-Touch Touchpad, Black - Walmart.com
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