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
Unifying Receiver 1 to 6 Devices USB Wireless Keyboard Dongle Mouse | eBay
USB Adapter Wireless Mini USB Bluetooth-compatible for Logitech Accessories Laptop Dongle Unifying Receiver - AliExpress
Pour Logitech Unifying Receiver USB Dongle Kit K800, K750, K710, K700, K520,K400 | eBay
Logitech Unifying Receiver for Connecting Multiple Devices
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