Foil Balloons are sensitive to extreme temperature changes. In cold air, they may appear deflated; warm air should expand them again. Extreme head could cause the helium to expand and burst the balloon.
Inflated with helium, this balloon will float up to 7 days and can be refilled.
Foil balloons may conduct electrity. Do not release helium-filled foil balloons outdoors or use near ovrhead power lines. Use only non-metallic ribon and attach the balloon to a weight to keep it from floating away.