Advanced Bionics Naida CI M90 Manuel D'utilisation page 35

Remove the Zn-Air cells from their package, making sure to remove the
sticker from the flat positive (+) side of the cell. Removing the sticker
allows air to enter and activate the battery, so be sure to use the battery
immediately after peeling off the sticker.
Place two Zn-Air cells, positive (flat) side up, in the two openings in the
battery drawer.
Once batteries are flush with the top of the battery drawer, gently
slide the battery drawer back into the battery cartridge. If the cells are
inserted incorrectly, the battery drawer will not close.
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