Review on Gigastone 256GB Micro SD Card | 4K Video Recording | Compatible with GoPro, Action Camera, DJI, Drone, Nintendo-Switch | Up to 100/60 MB/s R/W Speed | MicroSDXC Memory Card UHS-I U3 A2 V30 C10 | Includes 5-Yrs Free Data Recovery by Steven Asthana

This card tests around 50MB/s Write, 90+ MB/s Read with Blackmagic Disk Speed Test but fails by around 15% when used in Insta 360 One X 14 -20 minutes in the "Insufficient Speed" recording. This camera records two files simultaneously at around 6MB/s each, but recording something else at the same time prevents the Gigastone from delivering the results it promised. After trying to contact customer service: no support available. They contacted me, asked what resolution I was recording the video in, then fell silent. A star. For the same money you can buy a solid brand.