This is Micro SD/TF to SD Card adapter which perfectly fits into Raspberry Pi SD card holder. This low-profile Micro SD Card Adapter converts a Micro SD card for direct use with Raspberry Pi, without the use of a full size SD card.
The adapter is small which sits completely flush with the edge of the Raspberry Pi, that eliminated the risk of knocking your SD card out and no edge exposed outside card slot to avoid damage of card or main board. The whole adapter is hidden under the board.