Bracers of Blocking (3.5e Equipment)
From D&D Wiki
Bracers of Blocking: These Bracers give the wearer the unique ability to block mundane range and melee attacks. When the wearer is subjected to a melee attack the wearer has a 40% chance to block the incoming attack with their shield/weapon. If the wearer is subjected to a mundane range attack they have a 30% chance of blocking the attack. Each attack that is blocked from this ability does 0 damage.
Strong enchantment;CL 10; Strength 18+; Cost 10k gold; Weight: 3 IB lb.; Market Price: 20k