Bracers of Defense

Wondrous Item, Rare (Requires Attunement)

While wearing these bracers, you gain a +2 bonus to

An Armor Class (AC) is the target number for an attack roll. AC represents how difficult it is to hit a target.

Your base AC calculation is 10 plus your Dexterity modifier. If a rule gives you another base AC calculation, you choose which calculation to use; you can't use more than one. See also Attack Roll.

if you are wearing no armor and using no

AC: +2
Weight: 6 lb. Cost: 10 GP

.

Source: Dungeon Master's Guide, p. 241