Description: Plug and play (no software needed) Micro SD + TF format,High-speed read and write 4GB,8GB,16GB,32GB Storage Size Applies to Cell Phones, Cameras, MP3/MP4 Player and More device Operating Temperature -13ordm F to 185ordm F (-25ordm C to 85 ordm C) Storage Temperature -40ordm F to 185ordm F (-40ordm C to 85ordm C) Warm Tips ( 2.0USB reader Test Result) : 4GB/8GB/16GB/32GB-Class 10-SDHC Class10: Read speed around 18-22MB/S, Write speed around 10-15MB/S The Micro SD card speed is based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. Micro SD card speed is greatly affected by card reader, adapter, USB port etc. Low quality device will 100% slow down card speed. Hardware Features: Original high quality flash memory About capacity: 4GB=approximately 3.6GB-3.8GB 8GB=approximately 7.4GB-7.6GB 16GB=approximately 14.4GB-14.8GB 32GB=approximately 28.5GB-30GB