Ring of The Ox (3.5e Equipment)
From D&D Wiki
Ring of The Ox: Decorated with etchings of laboring oxen, this ring is made of a heavy iron alloy. Its wearer is able to carry a quarter more than his maximum carrying capacity. This affects lifting and dragging. Also, its wearer can walk for 12 hours without making a Constitution check and gains a +4 bonus each Constitution check required by a forced march.
Moderate transmutation;CL 7; Forge Ring, polymorph, bull's strength; Market Price: 26,950gp