The adapter has a normal-size USB type A connector and on the other side a small USB connector type A. also
I put a Micro SD card into the adapter. The adapter I put the small USB connector to my Samsung S4 Zoom.
There come the message "USB Mass Storage Device connected"
In the file manager, I find now the Micro-SD card as "UsbDriveA" ...
When I put the adapter on one side to the PC and on the other side of the Smartphon, is connected only one of the two devices with micro SD card.
Small drawback: The dust caps of the two USB connectors are transparent. When they fell down, the search difficult, because they are hard to see.