BacVex is a legendary Runeword created by combining a Bac Rune of Ritual and a Vex Rune of Invocation.
How to Create BacVex
You can create BacVex by adding the legendary Bac Rune of Ritual and the legendary Vex Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Bac - Travel 5 meters. (50)
Vex - Gain +3 to all Skills for 7 seconds. (1000)
Overflow
BacVex can not overflow because the amount of Offering you receive from the Bac 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.