NocVex is a legendary Runeword created by combining a Noc Rune of Ritual and a Vex Rune of Invocation.
How to Create NocVex
You can create NocVex by adding the rare Noc Rune of Ritual and the legendary Vex Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Noc - Inflict a Crowd Control that isn't Slow or Chill. (10)
Vex - Gain +3 to all Skills for 8 seconds. (1000)
Overflow
NocVex can not overflow because the amount of Offering you receive from the Noc Rune exactly fills the required Offering of the Vex Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.