The markings printed on the side of a card say more than capacity alone. V30 and U3 tell you the write speed is enough for 4K video, A2 speeds up app use on a phone, and UHS-I is the most common bus on today's cards. There are microSD cards from Kingston, SanDisk, ADATA and GoodRam from 16 gigabytes up to a terabyte, and the full-size SD cards that fit cameras form a group of their own; many microSD cards come with an SD adapter.
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The markings printed on the side of a card say more than capacity alone. V30 and U3 tell you the write speed is enough for 4K video, A2 speeds up app use on a phone, and UHS-I is the most common bus on today's cards. There are microSD cards from Kingston, SanDisk, ADATA and GoodRam from 16 gigabytes up to a terabyte, and the full-size SD cards that fit cameras form a group of their own; many microSD cards come with an SD adapter.