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
For Logitech K800,K750,K710,K700,K520,K400,360 Unifying NANO USB Dongle/Receiver – ASA College: Florida
Logitech K400 Plus Touchpad Keyboard for TV connected PC
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Logitech K400 Plus Wireless Touch TV Keyboard With Easy Media Control and Built-in Touchpad, HTPC Keyboard for PC-connected TV, Windows, Android, Chrome OS, Laptop, Tablet - Black - Newegg.com
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
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Logitech Unifying Receiver for Connecting Multiple Devices
Logitech K400 Plus Touchpad Keyboard for TV connected PC
Logitech K400 Plus TKL Wireless Membrane Keyboard for PC/TV/Laptop/Tablet with Built-in Touchpad Black 920-007119 - Best Buy
Logitech K400 Plus did not come with a USB dongle? Wait!! It's hidden in the box!! | THINKBOX
Logitech K400 (920-003070) Wireless Touch Keyboard WITH Unifying USB Receiver 97855074928 | eBay