Not Updated For Current Season
with this build you will end up with:
347 magic resist
and becouse your passive gives you 50%of your magic resist in AP,
in this case it will be: 173 extra AP.
but with these masteries your shield (W) gets 13,2% stronger, this means that
instead of 90 armor and magic resist you get 101.
with as result when you use your shield:
449 magic resist
and with your passive 224 extra AP....
and THAT is what i call a REAL AP TANK!