Breathing Bubble
Wondrous Item, common
This translucent, bubble-like sphere has a slightly tacky outer surface, and you gain the item’s benefits only while wearing it over your head like a helmet.
The bubble contains 1 hour of breathable air. The bubble regains all its expended air daily at dawn.
Source: Explorer’s Guide to Wildemount p. 266, Critical Role: Call of the Netherdeep p. 213