The patterns of the most complex magical formulae are like children's drawings to you. You treat any non-scroll activated equipped item that casts spells (such as wands, rods, armor, or other activated items) as if they were staves, increasing their caster level to equal yours as well as increasing Save DC's to (10 + your Intelligence bonus + level of spell) if it would be an improvement. These increases are applied after Artificer Knowledge, so do not stack.