SanDisk Extreme PRO 64GB CF Express Card Type B, up to 1500MB/s, for RAW 4K video

Amazon

Read speeds of up to 1700MB/s and write speeds of up to 1400MB/s offer low latency during high-speed recording and enhance workflow efficiency far beyond existing SanDisk cards Enables smooth, RAW 4K video The CFexpress Card Type B is backwards-compatible with select XQD cameras that adopt firmware enabling CFexpress RescuePRO Deluxe Recovery Software included (download required)

Currys

- With read speeds up to 1500 MB/s and write speeds up to 800 MB/s you can record RAW 4K video - The RescuePRO Deluxe3 software makes it easy to recover files that got accidentally deleted - It's shockproof, freezeproof and backed by a limited lifetime warranty