Robe of the Venerable Grandmaster

Wondrous item, legendary (requires attunement by a monk)

While wearing this robe, you gain the following benefits if you are wearing no armor and using no shield:

• You gain a +3 bonus to AC.
• Your martial arts damage die increases by one size. For example, a d10 martial arts die becomes a d12.
• You gain the effect of the haste spell (no concentration required).