Designed for capturing raw 8K, 6K, and 4K video, the 400GB CFexpress 4.0 Type B Iridium Memory Card from ProGrade Digital provides read speeds of up to 3550 MB/s, which helps to quickly offload content to your computer, and write speeds of up to 3000 MB/s. Additionally, the Iridium delivers sustained write speeds of 850 MB/s and, thanks to its VPG-400 rating, minimum write speeds that are guaranteed to not drop below 400 MB/s.