Lands of Algia 4E
Metal studs on this armor magically protect you from lightning, and then unleash that same power against your foes.
Enhancement: +1 AC
Property: You gain resist 5 lightning.
Power (Encounter): Free Action. Trigger: You take lightning damage. Effect: Until the end of the encounter, this armor’s daily power gains a +1 bonus to the attack roll and deals 1d10 extra lightning damage.
Power (Daily * Lightning): Immediate Interrupt. Trigger: An enemy adjacent to you targets you with an attack. Effect: Make an attack against the triggering enemy: +8 vs. Fortitude; on a hit, deal 2d10 lightning damage, and the enemy is dazed until the end of your next turn. Published in Adventurer’s Vault 2, page(s) 98.
Found in the main chamber of the Temple of Nerilous