Want to save space on your mobile device by running apps from a memory card? Transcend's micro SDXC/SDHC 300S cards are the right choice!. Compliant with the latest speed class, the cards boast excellent random read/write speed, perfect for retrieving small pieces of data from random locations & speeding app launch time. The Application Performance Class was introduced to adapt this new trend. Transcend's micro SDXC/SDHC 300S memory cards meet the new A1 standards, delivering minimum random read of 1, 500 IOPS & random write of 500 IOPS, & sustained sequential speeds of at least 10MB/s. A1 compliance applies only to 32GB-512GB capacity cards. 1 year warranty.