Speed:                                                                                                                                            
4GB - Class 4-6 SDHC
8GB/16GB/32GB- Class 10 SDHC
64GB/128GB- Class 10-SDXC
Class 6: Read speed around 15-20MB/S ,Write speed around 6-8MB/S
Class10: Read speed around 15-30MB/S ,Write speed around 9-12MB/S
 
1.The Micro SD card speed is based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors.
2.Micro SD card speed is greatly affected by card reader, adapter, USB port etc. Low quality device will 100% slow down card speed.
About capacity:                                                                                                                           

4GB=approximately 3.5GB-3.7GB

8GB=approximately 7GB-7.3GB

16GB=approximately 14GB-15GB
32GB=approximately 28GB-30GB
64GB=approximately 58GB-60GB
128GB=approximately 119GB-120GB
This is calculation difference between manufacturer and our PC, please Google 'Memory card capacity' to get more information
Features:                                                                                                                                    
Original high quality flash memory
Manufactured in Taiwan
MicroData Official Aliexpress Store offers 100% genuine memory card with 30 years warranty
Please don't use cheap card reader to test Micro SD card, speed of Micro SD card will be reduced by low quality card reader
Micro SD card speed is greatly affected by card reader, adapter, USB port etc. Low quality device will 100% slow down card speed.
Up to 20MB/s read speed; write speed lower. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes.