Review on HiLetgo Stackable SD Card Shield Module with 📷 SD/TF/Micro SD Card Reader for Arduino UNO R3 MEGA2560 by Jimmie Trotto

As others have said, this product should definitely come with basic documentation, at least a note card with configuration settings. It has a few jumpers that need to be set correctly, as well as a switch that needs to be in the correct position depending on the Arduino model you are using. If you pull out the SD card while it is in the reader, you can easily pull it out, so be careful. Note that the SCA and SLA connectors are shielded when attached, but you can put a curved jumper in them. Otherwise no problem, would definitely buy it again for another project.