+2 Dragonhide Belt
Wondrous Item, rare (requires attunement by a monk)
This finely detailed belt is made of dragonhide. While wearing it, you gain a +2 bonus to the saving throw DCs of your ki features. In addition, you can use an action to regain ki points equal to a roll of your Martial Arts die. You can’t use this action again until the next dawn.
Source: Fizban’s Treasury of Dragons p. 23