What does protective aura do?

[Jigga]

I tried searching, couldn't find any info

[Stalkerr]

#: 24, Name: protective aura, Short: prot, Magery: Mage-1, LVL: 5, Mana: 10, Diff: -15
>> Target: Self -- Cap: 30 -- M.R. 4+(0.2*lvl) to 3+(0.5*lvl), for 20+(0.7*lvl) rounds
(@lvl 5): M.R. +5, for 23 rounds
(@lvl 30): M.R. +10 to +18, for 40 rounds