Inside each barrel drum is a 1:64 scale Hot Wheels Color Shifters Monster Truck covered in special Color Reveal coating and a clip-on water tank. Fill the drum with water and swirl the truck until the water changes color, then pull it out to reveal its deco! To change its appearance again, fill the drum with ice cold water and dunk it in! Change back by dunking it in warm water! Use the clip-on water tank to spray oncoming Color Shifters trucks with deco-changing water. Each sold separately.