Rune of the Storm

Engrave your belt with the Maelstrom Weapon rune: When you deal damage with a melee attack, you have a chance to reduce the cast time and mana cost of your next Lightning Bolt, Chain Lightning, Lesser Healing Wave, or Lava Burst spell by 20%. Chance increased by 50% while your main hand weapon is enchanted with Windfury Weapon and by another 50% if wielding a two-handed weapon. Stacks up to 5 times. Lasts 30 sec.