Micro SD card that comes with an SD adapter. Works great in a phone Samsung Galaxy ACE. Card write fast enough (13Mb / s indicated on the packaging; they always extol "theoretical" speeds, but rather half practice -on "big" files- via a micro-SD USB adapter I had buy in addition, for my "old" multi-card reader only reads SDTrès satisfied, and this is an original product, in its new samsung blister.