SanDisk 400GB Ultra MicroSDXC UHS-I Memory Card with Adapter - 100MB/s, C10, U1, Full HD, A1, Micro SD Card - SDSQUAR-400G-GN6MA

Purchased 2 of these for our cell phones. ScanDisk has always worked great.

I bought this to add storage capacity to a SurfaceBook with a 512GB SSD. It adds 366GB of usable space which shows up as a separate USB drive in my computer's base directory. If you have a computer with a dedicated SD card slot, this MicroSD card can expand your laptop's storage without protruding beyond the edge of the notebook chassis if used with an adapter in place of a regular SD card (see the photos for how this works).And now the price for 400GB is a semi-reasonable $249, making this roughly $.62/gb. The cost per gigabyte sweet spot seems to lie at the 32-64GB level, with SanDisk storage in that size range costing $.30/gb and Samsung roughly the same. At this price, it's cheaper to throw a MicroSD card in a slot than to try to add storage to a non-upgradeable computer like the MacBook Pro or SurfaceBook. But if you do go this route, remember that flash memory of this sort is less-reliable than a disk. Don't use it for irreplaceable or mission-critical content.I use this BASEQI Aluminum MicroSD Adapter for Microsoft Surface Book & Surface Book 2 13.5" adapter. Other manufacturers also make adapters that permit a MicroSDXC card to be used in place of an SD card as a semi-permanent addition to laptop memory. The adapter allows the card to fit entirely within the laptop frame (usually impossible with full-size SD cards in modern laptops which only provide shallow ports), becoming nearly because the adapter's slim exterior portion matches the laptop's surface. Search the adapter maker's other listings and you will find similar products for MacBook Pros with SD card slots.Throughput between this and the laptop's internal SSD is passable, not great, averaging about 30 MB/sec with a folder filled with pictures. See pictures below for input and output benchmarks.

For dashcams and other continuous loop recordings: Sandisk markets a "high endurance" 256gb card @ $52, but it is a terrible deal compared to this 400gb SanDisk Ultra. The main selling point of a high endurance card is1) it can take additional writes. This card can too since it also has storage space above 256gb, except unlike the 256gb card you can access the additional storage space from the get go, which is hugely important to increase the look-back period of your dashcam. 256gb is the current max storage for high endurance cards, if you want more storage you either have to periodically back up data to a hard drive or... you could just get the 400gb Ultra.2) Some durability features. SD cards have zero moving parts, any condition that would destroy the Ultra would likely destroy the equipment containing it. There is only a narrow survivability delta, if any, where the high endurance would survive conditions that the ultra doesn't.3) Warranty. The high endurance only offers 2 years warranty compared to 10 years on the ultra, but in the warranty terms the Ultra does not cover failures due to use in applications like dash cams. This is BS as all SD cards are already warranty-limited by write cycles. Write cycles are write cycles, regardless of whether they occur in a dash cam or a normal camera. Nevertheless this warranty is unnecessary as a) failures of legit microsds are extremely rare even in "high endurance" scenarios, and b) the costs of cashing in the warranty likely exceed the value of the replacementIn terms of compatibility, many pieces of equipment will claim to have a limit of say 128gb but take this card just fine.In terms of write speed, a peak of 100MegaBytes/s is plenty for most consumer grade cameras. I've used it in an action camera and it can take sustained 4K 170 Megabits/s video (170 megabits = 20 MegaBytes) no problem.TLDR/Bottom line: If you can afford it and if you plan on using the card in a scenario where you might possibly, at some point need maximum storage, this is the option that provides the best value.

This was just what I needed to use with my digital camera. No problems. I appreciate its good quality, ample storage space, and value for money.

I love it! Works great in my Galaxy Note 8! Fast enough that I can throw pretty much anything at it. If you're wondering, modern Android versions (starting with Lollipop, as I recall) have the ability to read up to 1 TB of external storage. While this 400GB card is the maximum capacity you can currently buy*, the leading manufacturers are feverishly working to make larger capacity cards. For now, though, I think 400GB is enough to handle all the 4K video I can shoot.*- Don't be fooled by unscrupulous sellers, particularly on auction sites ( I won't name it because there are a lot of fake cards here, too), who list ridiculously large capacity cards for astonishingly low prices... you don't get what you pay for! They take cheap, generic cards, usually no more than 4 or 8 GB, and rewrite the card's firmware & re-label it to make it act and appear like a larger card... 256GB, 500GB or higher! There are tons of listings out there for 1 TERABYTE microSD cards! Of course there's no such thing: and when the physical memory of the card is reached, your device will simply start overwriting data... and your precious photos, videos and other files will be gone forever. In fact, one third of all SanDisk cards on the market are counterfeit! You can avoid all this by installing and using a free app called SD Insight to determine if your card is legitimate.