SD Cards

SD cards, short for secure digital cards, are compact memory cards commonly used for storage in portable devices. They are removable cards which store data from a device such as a digital camera or smartphone. Some PCs and laptops come with an SD card slot too, or you can purchase a card adapter separately. The compact nature of the card makes it easy to integrate into portable devices.

What size are SD cards?

SD cards come in three different physical sizes, standard, mini and micro. The size you choose depends on which device you plan to use and what card it can be used with.

Each SD memory card will have a capacity size too, given in GB or MB. This refers to the amount of data that can be stored on the card. Larger capacities will be more expensive so it is best to choose an SD memory card that meets your storage needs.

Why would you need an SD card?

Most devices today come with built-in memory storage to a certain capacity. However, it is very easy to use their internal memory up, and that is where SD cards are useful. They add-on to your personal device that can greatly boost the amount of media you can store at one time. You will not have to worry about having to delete important photos from your camera, or music from your smartphone.

With most SBCs, including Raspberry Pi, they run their OS from an SD Card. To shop Raspberry Pi micro SD cards preloaded with NOOBS, visit our sister site OKdo for all things Raspberry Pi and SBC.


  • SDUC stands for Secure Digital Ultra Capacity. This supports memory cards up to 128TB.
  • SDXC stands for Secure Digital eXtended Capacity. SDXC cards support up to 2TB.
  • SDHC stands for Secure Digital High Capacity. SDHC card refers to SD cards which have a higher storage capacity, usually over 4GB.

What is Speed Class?

Speed class is a standard developed by the SD association. Speed Class, UH Speed Class and Video Speed Class are given to indicate the minimum writing speed of a memory card. They include:

  • Speed Class - 2, 4, 6, 10
  • UH Speed Class - UHS-I, UHS-3
  • Video Speed Class - V6, V10, V30, V60, V90

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Description Price Card Format Capacity Industrial Speed Class Rating Nand Type Series Temperature Range X Speed Rating
RS Stock No. 144-8090
Mfr. Part No.DS2A-08GI81W1B
MicroSDHC 8 GB Yes Class 10 SLC - -40 → +85°C -
RS Stock No. 180-5815
MicroSDHC 4 GB Yes UHS-1 SLC - -40 → +85°C -