CirGar is a magic Runeword created by combining a Cir Rune of Ritual and a Gar Rune of Invocation.
How to Create CirGar
You can create CirGar by adding the magic Cir Rune of Ritual and the magic Gar Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Cir - Cast the same non-Channeled Skill 3 times in a row. (25)
Gar - Gain 2.5% Critical Strike Chance for 5 seconds, up to [2.5*10]%. (25)
Overflow
CirGar can not overflow because the amount of Offering you receive from the Cir Rune exactly fills the required Offering of the Gar Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.