256GB microSDXC UHS-I V30 SanDisk Extreme Pro 200MB/s Read 140 MB per second. Write a memory card for smartphones that support 4K video. Drones and action cameras: Boost the effectiveness of your workflow With fast read speeds of up to 200MB/s (64GB - 1TB), this card maximizes performance for time-saving media offloads thanks to SanDisk QuickFlow Technology. To get the fastest speeds, pair with the SanDisk Professional PRO-READER SD and microSDTM (separately sold). Write speeds