Hoodman STEEL is a Ruggedized CFexpress card line designed to withstand the rigors of high performance photography/videography. Your CFexpress card enabled camera bodies can run at peak performance levels - 1700MB/s read and 1400MB/s write. Card Type: CFExpress, Type B Capacity: 256GB Read Speed: 1700mb/s Write Speed: 1400mb/s Operating Temp: -13°F to +185° F (-25° C to 70° C) Dimensions: 1.17in x 1.52in x 0.15in (29.7 mm x 38.6 mm x 7.6 mm)