Logitech K400r Wireless Keyboard With Touchpad & Unifying USB Receiver - Tested | eBay
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 K400r Wireless Keyboard With Touchpad & Unifying USB Receiver - Tested | eBay
Logitech K400r Wireless Keyboard no unifying receiver – St. John's Institute (Hua Ming)
Genuine Logitech Unifying Mirco Dongle Receiver USB For keyboard K400r K400plus | eBay