Metallic Silver Foil Number '9' Balloon
*Foil balloons are sensitive to extreme temperature changes. In cold air they may appear deflated; warm air should expand them again. Extreme heat could cause the helium to expand and burst the balloon.
Foil Balloons may conduct electricity. Do not release helium filled foil balloons outdoors or near overhead power lines. Use a non-metallic ribbon and attach the balloon to a weight to keep from floating away.