This armor has a metal cylinder attached at the nape of the neck, and several tendrils reaching from the cannister to the armor’s reinforced pauldrons. As a reaction to taking acid, cold, fire, lightning, or thunder damage, you may activate the armor and gain one charge. While the armor is activated you have resistance to the damage type of the attack until the end of your next turn. Additionally, each time you take damage of this type while the armor is active the armor gains one charge.
As an action you may expend a number of charges to force all other creatures within a 10-foot radius to make a Dexterity saving throw, with a DC equal to 10 + your proficiency, as pure elemental energy is discharged from small holes in the pauldrons. Each creature takes 1d6 Force damage per charge expended on a failed save, or half as much on a successful one. All unexpended charges are harmlessly vented from the cannister each dawn.