Memory card selection guide
Which memory card speed class does your device need?
Start with the class named in the device instructions. Then check capacity and suitability for the actual workload.
U1 and U3 can support video recording. Resolution alone does not choose the card; match the device’s required class.
On this page
Start with the requirement on your device
| What you know | What to do | Why it helps |
|---|---|---|
| The manual says U1 | Choose U1 or U3 in a supported capacity. | Use the same class family and check repeated-recording suitability. |
| The manual says U3 or V30 | Match that symbol or a higher class in the same family. | U3 and V30 share a number but are not interchangeable certifications. |
| You only know 1080p or 2K | Look up the model’s card requirements. | Resolution alone does not show the recording rate. |
| The card holds songs or lessons | Check capacity, audio formats and playback. | A higher video class does not fix an unsupported file. |
Read the marks without mixing them up
MB/s means megabytes per second; Mbps means megabits per second. One byte equals eight bits.
| Mark | What it means | What it does not tell you |
|---|---|---|
| C10 / U1 / V10 | At least 10 MB/s under each class’s standard conditions. | They are different class families. |
| U3 / V30 | At least 30 MB/s under their respective standards. | Neither states card lifetime. |
| A1 / A2 | A1 and A2 rate performance for running apps, including reading and writing many small files. A2 needs a compatible device to deliver A2 performance. | They do not replace a video-class requirement. |
| UHS-I | Ultra High Speed I: the interface between the card and device. | The Roman numeral is not U1. |
Is the large speed number the recording speed?
A package may advertise maximum reading speed. Recording needs sustained writing speed. Two 12 Mbps cameras write 24 Mbps in total, or 3 MB/s after dividing by eight; the device requirement and writing peaks still matter.
Method & sources
Sources and practical limits
Method: Standards explainer based on the public SD Association definitions linked below. It separates label families before applying host documentation and device testing.
Limitations: This page does not confirm which marks are available on a current YOULEN series or capacity. Confirm the exact product configuration in the enquiry and order.
Published by Shenzhen Youlen Electronics Co., Ltd.
SD Association: Speed Class SD Association: Application Performance Class