SD card labels: match U1, UHS-I and video classes before buying

First check the card family and capacity

Find the storage section of the exact device manual. Record whether it accepts SD or microSD, which card family it supports, and any stated capacity limit. The SD Association's compatibility guide distinguishes SD, SDHC, SDXC and SDUC hosts. For example, an SDHC host does not gain SDXC support merely because a card can physically fit.

Keep the device model in your notes. Another generation from the same camera or phone range is not a substitute for its manual. A storage-capacity number answers how much the card can hold, not whether the device supports it or whether its performance suits the selected task.

Separate the labels before comparing cards

• C10: Speed Class 10, a minimum sustained write-speed class of 10MB/s.
• U1 and U3: UHS Speed Class ratings of 10MB/s and 30MB/s respectively.
• V10, V30, V60 and V90: Video Speed Class ratings with the corresponding minimum write-speed number.
• UHS-I or UHS-II: interface names, not the same thing as U1 or U3.

Kingston's speed-class explanation distinguishes the class ratings from bus-interface transfer capability. These figures describe standards, not measurements of any individual card sold by Buy2Fix.

Do not replace a required symbol with another merely because both mention the same number. The SD Association recommends matching the host's class symbol, with the same or a higher class within that system. Its guidance specifically warns that equivalent numbers across different class systems do not establish the expected write performance. Follow your device's own requirements for the recording mode you intend to use; “4K” alone is not a complete card specification.

What about A1 and A2?

A1 and A2 describe Application Performance Class, addressing random-access as well as sequential performance. They are not substitutes for a camera's required video class. The SD Association's application-class guidance says A2 performance requires both an A2-supporting host and an A2 card. An A2 label does not establish that a phone allows apps to be installed on removable storage; check the phone's documentation separately.

Read a listing as evidence, not a completed compatibility check

If your device requirements point towards a 32GB microSD option, you can compare the MICRODATA 32GB U1 microSD card listing with your recorded requirements. The listing identifies 32GB capacity and U1 in the product name. That makes it a relevant example to inspect, not a recommendation for a particular recording device.

The page also gives a “60MB/s” figure without identifying it as a minimum sustained write speed. Do not reinterpret that as V60, or infer V30, A2 or a particular camera's approval. If your manual requires a rating the listing does not establish, ask for the exact card specification or choose an option with the required evidence before ordering. No card performance, endurance, authenticity or device compatibility has been independently tested for this guide.

A before-you-buy matching worksheet

1. Device and job: exact model; file storage, a named recording mode or another documented use.
2. Physical format: SD or microSD, as specified by the device.
3. Family and capacity: required SD-family support and permitted capacity.
4. Performance symbols: copy the manual's symbols exactly rather than rewriting them as a single MB/s number.
5. Candidate evidence: record each matching label from the exact listing/specification; mark anything missing “unknown”.
6. Decision: buy only after the requirements match; otherwise request clarification. Keep a copy of the specification used.

For a worked comparison, suppose a manual explicitly requires V30. A candidate showing only U1 and an unexplained “60MB/s” number does not establish that requirement. That is a missing-evidence result, not proof the card is defective. Conversely, an impressive maximum transfer figure cannot override an unsupported card family or capacity.

What this checklist cannot prove

Labels and listings are a starting point, not a laboratory test or counterfeit assessment. They do not guarantee recording duration, recovery of damaged files or service life under continuous recording. Follow the device manufacturer's specific recommendations and keep important files backed up. Do not format or erase an existing card just to perform this purchasing comparison.