This product is either discontinued or we cannot get that from suppliers.
Logitech 910-005239 Usb Unifying Receiver Connects, Wireless Keyboard Mouse Multiple 6 Devices, Compatible devices Windows® 10 or later, Windows 8, Windows 7 Mac OS® 10.10 or later.
Connect up to 6 compatible keyboards and mice to one computer with a single Unifying receiver – and forget the hassle of multiple USB receivers.