The SanDisk SDSDXXY-256G-GN4IN is an Extreme Pro Memory Card with SD XC, UHS-I and 256GB capacity. It can read data at up to 170MB/s, making it ideal for recording and playing back HD video media, quickly accessing files, and transferring large files between devices with minimal wait times. It is shockproof, temperature-proof and X-ray-proof, making it reliable for shooting photos and videos in hostile environments like extreme temperatures, air pressure, and locations exposed to x-rays.