Canon MG6400 series Online Manual page 147

Insert the following types of memory cards into the lower card slot:
SD Secure Digital memory card, SDHC memory card
miniSD Card , miniSDHC Card
microSD Card , microSDHC Card
Important
Part of the memory card will protrude from the card slot, but do not force it into the
slot any further. This can damage the machine or the memory card.
Make sure that the memory card is correctly oriented before inserting it into the card
slot. If you force the memory card into the card slot in the wrong orientation, the
memory card or the machine can be damaged.
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