Amazon.com : Original Replacement USB Receiver for Logitech Wireless Presenter R400 and R800 : Office Products
Marcus Mengs on Twitter: "New receiver for @Logitech R400 presentation clicker mitigates wireless keystroke injection. Had 5 minutes to test a replacement receiver. The new ones marked with 'ESW3601' restrict injectable keys
Logitech R400 presenter pen USB 2.4G Wireless RF Remote control IR PPT Presenter Laser Pointer with Red Laser Retail packaging|pointer presenter|pen iphonepen laser pointer - AliExpress
Zotech Replacement USB Receiver (C-U0014) for LogitechWirelessPresenter R400/R700/R800 - Not Compatible with All R400/R700/R800 Models (See Details Before Buying) : Electronics - Amazon.com
Amazon.com : Original Replacement USB Receiver for Logitech Wireless Presenter R400 and R800 : Office Products
Replacement USB Receiver for Logitech Wireless Presenter R400 & R800 | iSeaClear, Inc.
New USB Receiver for Logitech Wireless Presenter R400 R700 R800 (C-U0014) 702534996667 | eBay