Wandjinamet

is a Noble Phantasm of the Wandjina. It is a continuously-active type Noble Phantasm that is worn over their head like a helmet.
Wandjinamet combines the concept of water or rain in the atmosphere, which the Wandjina calls “Droplet”. Even though a normal person who puts it on would be soaked as if they had thrust their head underwater, there’s no question over why they wouldn’t drown. The Wandjina is an Elemental who gives blessings unto life. Even if a human touches this equipment, they will not be harmed. If anything, they will be vitalised―their life force will be invigorated.Fate/Grand Order - Wandjina Max Bond Craft Essence: "Wandjinamet" - Translated by Justiciar_Jyggalag
But it would be wise to exhibit caution. This “Droplet” is just one or two steps shy of being an Authority. If one were to try and take it from the Wandjina by force, then the culprit will undoubtedly be up a creek without a paddle. Even if the Wandjina theirself isn’t angered, there is a very high likelihood of other Elementals, Fairies, or even Divine Spirits being outraged. 
So even if the Wandjina leaves it carelessly lying around, you’d do well to be extremely careful.
==References==
Category:Unknown rank Noble Phantasms
Category:Unclassified Noble Phantasms
Category:Armor
Category:Noble Phantasms
Category:Noble Phantasms introduced in Fate/Grand Order
Category:Continuously Active-Type Noble Phantasms