SANDISK 256B Extreme microSD Card + Adapter, Up to 245MB/s Read Speeds
Bottom line: The SANDISK 256B Extreme microSD Card + Adapter ($74.99 on Amazon as of 2026-10-06): 245MB/s read and 170MB/s write rated at this 256GB capacity; main trade-off: peak 245MB/s read applies to 256GB-1TB capacities, not smaller cards.
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*Price sourced from Amazon.com. Last updated 2026-10-06. Price and availability subject to change.
Pros & Cons
Pros
- ✓ 245MB/s read and 170MB/s write rated at this 256GB capacity
- ✓ U3 and V30 ratings sustain 5.3K and 4K UHD video without dropped frames
- ✓ Waterproof, shock proof, drop proof, magnet proof, X-ray proof, temperature proof
- ✓ SanDisk Memory Zone app backs up and transfers on desktop or Android
Cons
- ✗ Peak 245MB/s read applies to 256GB-1TB capacities, not smaller cards
- ✗ UHS-I bus caps speeds below UHS-II cards used in higher-end cameras
- ✗ Rated speeds require a host device and reader that support them
- ✗ No SD adapter listed in the product details, so check before use in a camera
Manufacturer description
CAPTURE LARGER THAN LIFE. Unlock startling 5K[3] point-of-view and pristine high-res stills with video speed class ratings of U3 and V30[4]. SPEED BARRIERS SHATTERED. Save precious moments with rapid read speeds up to 245MB/s[2] and write speeds up to 170MB/s[2] [256GB-1TB capacities[1]]. MAXIMIZE WITH MASSIVE CAPACITY. Record longer and store more with up to 2TB[1] of storage.
SpecPicks Verdict
SpecPicks scored SANDISK 256B Extreme microSD Card + Adapter using a rating × review-volume × price-fit model applied to published specs and reviews across the external storage category. Sandisk's external storage lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.
Common buyer scenarios for external storage of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.
Frequently Asked Questions
How fast is the SanDisk Extreme 256GB microSD card?
SanDisk rates it at up to 245MB/s read and up to 170MB/s write, and those figures apply to the 256GB through 1TB capacities.
Can it record 4K video?
Yes. It carries U3 and V30 video speed class ratings and is rated for 5.3K and 4K UHD capture, which are the classes action cams and drones require for sustained 4K recording.
Will this work in a GoPro or a drone?
It is marketed for action cams, drones, and Android devices, and its U3/V30 ratings match what those devices specify. Check your camera's supported card list for capacity limits.
Is it waterproof and durable enough for outdoor use?
SanDisk lists it as temperature proof, humidity proof, waterproof, shock proof, drop proof, magnet proof, X-ray proof, and wear-out proof.
What warranty does this card come with?
Warranty terms are not listed in the product details here. Check the current product listing or SanDisk's site for the warranty that applies to your region.
Key Features
- CAPTURE LARGER THAN LIFE. Unlock startling 5K[3] point-of-view and pristine high-res stills with video speed class ratings of U3 and V30[4].
- SPEED BARRIERS SHATTERED. Save precious moments with rapid read speeds up to 245MB/s[2] and write speeds up to 170MB/s[2] [256GB-1TB capacities[1]].
- MAXIMIZE WITH MASSIVE CAPACITY. Record longer and store more with up to 2TB[1] of storage.
- DURABILITY YOU CAN COUNT ON. SANDISK microSD cards are temperature proof, humidity proof, waterproof, shock proof, drop proof, magnet proof, X-ray proof and wear-out proof[7].
- EASY CONTENT MANAGEMENT. Easily back up, organize, and transfer your photos and videos with the SANDISK Memory Zone desktop or Android mobile app[10].
Full Specifications
| Size | 256GB |
|---|---|
| Brand | Sandisk |
| Color | Not Available |
| Model | SDSQXH9-256G-GZ6MA |
| Warranty | Lifetime Limited |
| UnitCount | 1 |
| ReleaseDate | 2026-03-04T00:00:01Z |
| Manufacturer | Sandisk Technologies, Inc. |
| ItemPartNumber | SDSQXH9-256G-GZ6MA |
Ready to buy?
SANDISK 256B Extreme microSD Card + Adapter, Up to 245MB/s Read Speeds is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
*Price sourced from Amazon.com. Last updated 2026-10-06. Price and availability subject to change.
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