Fusion Color Changing Bag by Henry Evans - Trick

A yellow silk is put in a bag and changes to red, this is repeated until the magician says he will explain it: He shows two silks, red and yellow; now they are put both put back in the bag and they change to blue, the same color of the bag's interior, which is now shown to be red and yellow!

Comes with Fusion Color Changing Bag, and instructions.