Source: Waterdeep - Dragon Heist

Wondrous item, very rare (requires attunement by a creature with a humanoid build)

The Masked Lords of Waterdeep don this ensemble when meeting with one another. This raiment renders each lord indistinguishable from the others. The ensemble consists of three pieces — a helm, an amulet, and a robe — that function as a single magic item when worn together, but only within the city of Waterdeep and its sewers. You become attuned to the ensemble as a single item.

Lord's Helm. This bucket helm covers your head and conceals your face. Screens over the eyes help to shroud your identity without blinding you. While you wear the helm, your voice is magically altered to sound genderless, and you are immune to magic that allows other creatures to read your thoughts, to determine whether you are lying, to know your alignment, or to know your creature type. Creatures can communicate telepathically with you only if you allow it.

Lord's Amulet. This amulet bears the crest of Waterdeep. It functions as an Amulet of Proof Against Detection and Location .

Lord's Robe. This elegant robe functions as a Ring of Free Action , and it creates the illusion that you have a nondescript. androgynous humanoid build and stand 6 feet tall.