CFExpress Type B 256GB Card (1700/1100 R/W) - Dual Pack

Our review of the CFExpress Type B 256GB Card (Pack of 2) looks at whether these cards deliver the real-world speed and reliability demanded by high-end mirrorless and cinema shooters. The bottom line: this dual pack is aimed at photographers and videographers who need very fast read and write bandwidth for uninterrupted 4K RAW capture and rapid offload, and its single biggest reason to buy is the high 1700 MB/s read and 1100 MB/s write performance when used with a PCIe host adapter.

Key Features

• Next-generation transfer: The CFExpress Type B interface enables cinema-quality 4K and burst RAW capture with much higher sustained throughput than older formats.
• High read speed: A tested 1700 MB/s read rate helps clear buffers quickly and shortens transfer times to a workstation when used with a PCI Express host adapter.
• Fast write performance: Up to 1100 MB/s write speed supports long continuous recordings and dense burst sequences without dropped frames.
• Rugged design: Shock- and vibration-resistant construction helps protect data integrity during active shoots in demanding environments.
• Wide compatibility: Works with many Canon and Panasonic cameras including R5, EOS-1DX Mark III, C300/C500 Mark III and S1/S1R when the camera supports CFexpress Type B.

Who It's For

The dual 256GB pack is best for professional and enthusiast users who record heavy 4K RAW or high-frame-rate video and need quick turnover between shoots; wedding shooters, commercial videographers, and wildlife photographers will appreciate the large capacity and sustained speeds. It is also useful for creators who move large files to workstations frequently, since the high read speeds reduce post-production wait time.

Those who should look elsewhere include owners of unsupported camera brands: these cards are not recommended for Nikon cameras and will not deliver benefits if your camera does not support CFexpress Type B. Buyers who only capture occasional JPEG stills or lightweight Full HD video may find less expensive storage options more practical.

Pros & Cons

Pros

• High sustained write speeds enable long continuous RAW 4K recording with minimal risk of dropped frames.
• Very fast read performance speeds up file transfers to a computer using a PCIe host adapter.
• Durable shock-resistant build helps preserve data during active shoots in harsh conditions.
• Two-card pack offers capacity redundancy and flexibility on location.

Cons

• Compatibility is limited to cameras that explicitly support CFexpress Type B; it is not recommended for Nikon models in this listing.
• Some buyers report mixed functionality in individual units, so testing cards before critical shoots is prudent.

Specifications

Format	CFexpress Type B
Capacity	256GB per card (Pack of 2)
Read Speed	Up to 1700 MB/s (tested with PCIe host adapter)
Write Speed	Up to 1100 MB/s (tested with PCIe host adapter)
Compatible Cameras	Panasonic S1 / S1R, Canon EOS-1DX Mark III, Canon EOS R5, Canon EOS C300 / C500 Mark III
Ruggedness	Shock- and vibration-resistant design

Our Verdict

The CFExpress Type B 256GB dual pack is a strong value for shooters who require dependable high-speed storage for 4K RAW and continuous burst work; the tested 1700/1100 MB/s performance and rugged construction justify it for professionals using supported Canon and Panasonic bodies. Buyers should confirm camera compatibility beforehand and test each card on arrival to ensure consistent functionality.

Frequently Asked Questions

Will these cards work with Nikon cameras?
These cards are not recommended for Nikon cameras in this listing; verify your camera explicitly supports CFexpress Type B before purchasing.

Do I need a special adapter to reach the listed speeds?
To achieve the quoted 1700 MB/s read and 1100 MB/s write speeds you must use a compatible PCI Express host adapter or a camera with native CFexpress Type B support and appropriate firmware.

Are both cards identical in performance?
They are sold as a matching pair, but some customers report mixed functionality on individual units, so it is advisable to test each card before critical use.