ADATA microSDXC Card High Endurance 256 GB. SD card, UHS-I U3 Class 10 V30 A2, 256 GB. UHS-I bus system. UHS-I compatible SD cards enable theoretical data transfer speeds of up to 104 MB/s. The speed class is indicated as U1 or U3: U1 for Full HD videos and U3 for 4K videos. SD cards with UHS-I support are backward compatible and can be used in devices without UHS support (with limited performance).

Speed Class: The Speed Class indicates the minimum continuous data transfer rate when writing video files to a memory card. The Speed Class number shows the transfer rate in megabytes per second. Class 2 cards are designed for a minimum continuous transfer rate of 2 MB/s, and Class 10 for a minimum continuous transfer rate of 10 MB/s. The speed classes are divided into classes 2, 4, 6, and 10. For Full HD video (1080p), Class 6 is recommended at a minimum.

Application Performance Class A2: This card is optimized for apps, providing fast startup and enhanced performance for your mobile applications. The App Performance Class is particularly important for SD cards used in smartphones and tablets. The A2 symbol indicates that the SD card meets the requirements of the corresponding App Performance Class 2 (A2): at least 4000/2000 IOPS for random and at least 10 MB/s for sequential transfers.

Video Speed Class: The Video Speed Class includes five speed levels V6, V10, V30, V60, and V90, with the number indicating the minimum write speed in megabytes per second (MB/s). By combining a device with a Video Speed Class designation and an SD memory card with the same Video Speed Class designation, you can capture memories in the best quality. The fastest options, V60 and V90, are supported.