Ring of The Boar (3.5e Equipment)
From D&D Wiki
Ring of The Boar: This ring has a carving of a boar’s tusked head as its insignia. It grants its wearer a +2 enhancement bonus to his existing natural armor. Also, he gains the extraordinary ability to fight without penalty while disabled or dying.
Moderate transmutation;CL 7; Forge Ring, polymorph, barkskin’’; Market Price: 26,950gp