Part of the Soulforge Armor set:

The set gives these bonuses as more pieces are worn: 2: +8 All Resistances. 3: Restores 8 mana per 5 sec. 4: Chance on melee autoattack and spellcast to increase your damage and healing done by magical spells and effects by up to 65 for 10 sec. 5: When struck by a harmful spell has a 7% chance of Silencing the caster for 3 sec. Can only occur once every 60 sec. 6: Increases damage and healing done by magical spells and effects by up to 23. Set Details | All Sets