The material below is Open Game Content from a 3PP Source
Ring of Retribution
Aura strong evocation; CL 13th
Slot ring; Price 15,000 gp; Weight —
Once per day, the wearer of this charred bone ring may, as an immediate action, cause it to detonate in a 30-foot-radius burst that deals 10d6 points of fire damage (Reflex DC 14 half). If the wearer is killed by the detonation, all magical equipment he carries must also save or take fire damage, and all nonmagical equipment takes this damage with no saving throw. This explosion never destroys the ring.
Requirements Forge Ring, Quicken Spell, fireball; Cost 7,500 gp