Third Lung Bag

Wondrous item, uncommon

This canvas bag has a pattern resembling the bronchial airways embroidered on either side. At its top is a metal valve. The bag holds 10 minutes of air and regains 1d10 used minutes daily at dawn. You can use an action to inhale 1 or more minutes' worth of air from the bag. Unless you speak or otherwise exhale, you don't have to breathe again for that number of minutes.

It'll hold your breath for you.