Dye Tube with Two Silks (watch video).
Effect
You start by showing both hands empty. Then you take a silk and push it into the top of your fist. When it emerges from the bottom, it will change colors. If you want, the silk can be immediately changed back to the original color.
Supplied with dye tube, 2 silks (colors vary), and illustrated instructions.
Dye Tube with Two Silks (watch video)