Micro SD cards, sometimes referred to as microSD, are memory cards used to store data in small devices. SD stands for secure digital and micro comes from its size. The microSD card is the smallest of the SD memory card family. What are micro SD cards used for?These memory cards are popular in portable devices, such as smartphones. Their compact size makes them ideal for smaller devices. If you would like to use your microSD memory card in a standard SD slot, you can purchase adapters separately. SD adapters enable you to connect your microSD card to SD or USB slots, for example, in PCs and laptops.What is capacity?Memory card capacity represents the amount of data that can be stored on the card. This is given in MB or GB, for example 4GB. Larger capacity memory cards tend to be more expensive. Therefore you should choose a card which is suitable for the amount of data you wish to store. What is SDUC/SDXC/SDHC?microSDUC stands for Secure Digital Ultra Capacity. This supports memory cards up to 128TB.microSDXC stands for Secure Digital eXtended Capacity. SDXC cards support up to 2TB.microSDHC 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, 10UH Speed Class – UHS-I, UHS-3Video Speed Class – V6, V10, V30, V60, V90