Meet the best of our best. The Pro Ultimate Sd card offers our fastest speeds and high storage capacity to keep up with any endeavor. Lightning fast read and write speeds help you win your workflow while compatibility with DSLRs, PCs and more power you through your creative pursuits. 1The foregoing read and write speeds are based on tests conducted under controlled conditions. Actual speeds may vary depending upon card capacity. Stated performance was achieved by using Pro Ultimate Sd cards with Samsung readers. 2UHS Speed Class 3 designates a performance option designed to support 4K Uhd video recording with enabled Uhs host devices. Uhs Video Speed Class 30 (V30), sustained video capture rate of 30MB/s, designates a performance option designed to support real-time video recording with Uhs enabled host devices.