Ring of 3 walls has 3 defenses. It has 4 charges. 

First charge used is a free action.

User gets Advantage on ability checks.

Resistance to Bludgeoning, Piercing, and Slash damage dealt from non-magical weapons. 

A magical divine trident comes out once thrown disappears. It deals 3D6 damage.

Other rings can not be used with 3rd Wall Ring. Must choose what ring you use or you default to the ring you got first.

Notes: Damage: Piercing, Advantage: Ability Checks, Resistance: Bludgeoning, Piercing, and Slashing from Nonmagical Attacks, 3 days with the ring, must have 2 other rings.