Chains of the glorious battlemage (3.5e Equipment)
From D&D Wiki
Chains of the glorious Battlemage: These mithral chains have the appearance of robes and radiates either a good (01-45) neutral (46-75), or evil aura (76-100). Its wearer, if an arcane spellcaster, gains the following powers.
10 armor bonus to AC, 5 max dexterity bonus. Spell resistance 18. arcane spell failure 20% +4 resistance bonus on all saving throws. +2 enhancement bonus on caster level checks made to overcome spell resistance.
If the chains with a good aura is donned by an evil character, she immediately gains three negative levels. The reverse is true with respect to the evil chains donned by a good character. An evil or good character who puts on chains with a neutral aura, or a neutral character who dons the chains of either alignment, gains two negative levels. While these negative levels never result in lost levels, they remain as long as the chains are worn and cannot be overcome in any way (including restoration spells). These chains also require light armor proficiency.
if your are not an arcane spell caster it is simply +5 mithral chainmail armor
These chains are an alternative to the Robe of the archmagi originally created by wizards of the coast for the 3.5 version of DnD