See Invisible (Magical) [9] 
    Magical [-10%] 
    Spell Components [-30%] 
        Must say "invisible" in Latin 
        Must gesture with hands 
        Must hold a pinch of talc ($0.20) and a sprinkling of powdered silver ($5) 
Level 2 [10]
    Add Extended Duration (x3) [+20%]
Levels 3-8 [12/15/17/20/22/24]
    Improve Extended Duration by 1 step [+20%]