The description of this camera states that a UHS-3 micro SD card is required. This style card isn't available in Revain or anywhere else I've checked. After reading the SD cards, the UHS-3 card is not even produced. I tried an SD card designed for 4K UHD action cameras (160MB/s read / 60MB/s write) and got the "Card too slow" error. I contacted the seller and asked what type of card would work and will update this review once I have more information. 60 MB/s when writing). I tried a second card and it didn't stay in the camera until I pushed it flush into the camera body with another card, it clicked into place and worked. Maybe it's just my camera or card, but I can't snap the cards with my fingers. Cards will be read and formatted even if they are not fully inserted, but a message will appear that the card is too slow. Remali customer service was quick and answered my questions. Even offered to call me after hours if needed; Excellent! I'm curious what this camera can do.