Buy Ghostbusters Proton Backpack Movie Prop Replica by VikingProps at Wish - Shopping Made Fun
Mattel& Ghostbusters Neutrino Wand Prop Makes Us Wish Ghosts Were Real
This is what I'm talking about. The full ghostbusters backpack experience!
Ghostbusters Electronic Proton Pack Projector Toys Kids Awesome Christmas Gift #Mattel
Ghostbusters - a quick and easy proton pack from Instructables using cardboard, tubing from hardware store and some chemical lights if you're fancy.