Two USB receivers for Logicool mice (CU0019). The receiver on the left in the image makes a "beep!" recognition sound when plugged into a PC's USB port, but nothing is displayed in Device Manager. The receiver on the right in the image is displayed as an "Unknown USB Device" in Device Manager. (Please refer to the 3rd and 4th images for the display in Device Manager.) This is a junk item (= no operational guarantee). Please refer to the following PDF for how to pair CU0019 with a mouse: https://www.logitech.com/assets/65976/2/usb-receiver-cu0019-qsg.pdf I cannot verify functionality because they do not work, but according to eBay, they seem to be usable with M170, M171, M185, and M186. #Logicool #Logitech #USBReceiver #receiver #CU0019 #C-0019 #Junk #Unrepairable #MysteryItem #Mouse #mouse #M170 #M171 #M185 #M186