Our most powerful SD UHS-I memory card yet saves you time transferring media with read speeds of up to 250MB/s(1) powered by SanDisk QuickFlow Technology(2). Pair with the SanDisk Professional PRO-READER SD and microSD to achieve maximum speeds (sold separately). With shot speeds of up to 150MB/s(1) and UHS speed Class 3 (U3)(4)recording, you're ready to capture stunning, high-resolution, stutter-free 4K UHD video(3) | (1)Up to 250MB/s read speeds, engineered with proprietary technology to reach speeds beyond UHS-I 104MB/s, require compatible devices capable of reaching such speeds. Write speed up to 150MB/s. Based on internal testing; performance may be lower depending upon host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes. X = 150KB/sec. (2)SanDisk QuickFlowTechnology is only available for 64GB, 128GB, 256GB, 512GB, 1TB and 2TB capacities. 1GB=1,000,000,000 bytes. 1TB=1,000,000,000,000 bytes. Actual user storage less. (4)UHS 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. See the SD Association's official website. (3)Full HD (1920x1080) and 4K UHD (3840 x 2160) video support may vary based upon host device, file attributes and other factors. See HD page on SanDisk site.