The label was implemented by the SD Association, which is the specification group for SD cards, and it falls under the new specification 5.1, which is about to roll out.

If you are going to use the SD card for recording video, for example, you should look for markings like V30 or similar on the label. But what does V30 on an SD card actually mean?

The 'SD' stands for Secure Digital, but it originally stood for something entirely different. If you examine the SD logo stamped on an SD card or card reader, you may notice that the 'D' is shaped ...

Its label also fell off when I pulled it out of the computer’s SD card slot: more strangeness. So, further feeding the curiosity beast, after clumsily gluing the label back on, I ran Blackmagic’s Disk ...

Good news: The SD Association has added yet another confusing specification layer to SD cards. The new "UC" spec extends the maximum capacity of either a full-size or micro SD card from 2TB to 128TB.

The big question is how much a 4TB UHS-1 SD card will cost. Given the 1TB versions of the same card retail for around $140, you’re probably looking at $600 or more for a 4TB version.