Amazon.com: Logitech New Unifying USB Receiver for Mouse Keyboard M515 M570 M600 N305 MK330 MK520 MK710 MK605 : Electronics
Logitech USB Dongle Extender - Works with Unifying Receiver
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
New Usb Receiver Wireless Dongle Receiver Usb Adapter For Logitech Mk220/mk270 X6hb - Mice & Keyboards Accessories - AliExpress
Logitech Unifying Receiver 1 to 6 Devices USB Dongle for Wireless Keyboard Mouse for sale online | eBay