the 256GB Elite-X UHS-I microSDXC Memory Card from PNY features a storage capacity of 256GB and takes advantage of the UHS-I bus to support read speeds of up to 100 MB/s. This Elite-X card supports the V30 speed class, which guarantees minimum write speeds of 30 MB/s. If your device does not support the V30 speed class, this card also supports the U3 speed class, which likewise guarantees minimum write speeds of 30 MB/s. If your device only supports the Class 10 standard, minimum write speeds are guaranteed not to drop below 10 MB/s.