If you have ever installed Custom Firmware on a PlayStation Vita or a PlayStation TV you will be familiar with this device: the SD2VITA. It allows you to use a regular Micro SD card instead of the proprietary and expensive Sony memory card.
While the adapter itself is straight forward, if you have ever tried to buy one, the number of variants and models is somewhat confusing. V1, V3, V5, some with a plastic case, some are just a raw PCB.
Twitter user Samilop “Cimmerian” Iter has written up a brief history of the adapter on his Vita troubleshooting guide page. It is an entertaining read about the first attempts to create such an adapter and the various revisions and creators who tried (and sometimes failed) to make their own new variants.