A Shohki mask [1] is designed to protect the wearer from the miasma in the Sea of Corruption. The mask contains ashes from the Toritsuma herb to filter the miasma. There are a variety of different models of this type of mask as it is common to any group that lives near the Sea of Corruption.
Nausicaä has a Shohki basket for Teto [2] when she flies into the Sea of Corruption. The basket has a filter on top and a viewport for Teto to look out of.
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a See Page Conversions Between Editions to convert Deluxe Edition volume 1 (DE1) to other editions