Lexar 667x 64GB Pro MicroSDXC

The video speed class indicates the maximum sustained read and write speeds of a memory card or storage device when recording or transferring video, expressed as a standard code such as V10, V30, V60, or V90. It helps users compare how quickly a device can handle high‑definition video streams and ensures compatibility with camera or recorder requirements.

The X‑Speed rating indicates the maximum sustained write speed of a memory card, expressed as a numerical value that represents the number of megabytes per second (or an equivalent performance metric). A higher number generally means faster data transfer and better performance for high‑resolution video or rapid image capture. The rating is used by manufacturers to differentiate cards within the same class (e.g., UHS‑I, UHS‑II) and helps consumers choose a card that meets their speed requirements