Increased speed, no increase in cost Premier microSDHC/SDXC UHS-I Class 10 U1memory cards have higher capacity, but without a higher price, and provide consumers with the faster read speeds of UHS-I specification at the price of a Class 10 card. Sequential reads are up to 50 MB/second, and write speeds reach the UHS-I speed class 1 specification. Random read and write IOPS are 1400 and 100 respectively. They are remarkably suitable for users who enjoy high definition photography and video recording. Running multiple applications simultaneously causes no loss in read/write speed. Durability These memory cards employ Error-Code Correction ECC, and are extremely cold-resistant, heat-resistant and impervious to x-rays, making them one of the world's most rugged memory cards.