Foil balloons are ideal if you want your balloons to float for a longer time than latex balloons. Foil balloons will least 5-7 days, or even longer. Foil balloons must never be released as they can conduct electricity if they come into contact with power lines. Foil balloons are not biodegradable.
Only biodegradable balloons are latex balloons, which are made from natural latex, not plastic.
Plain foil balloons come in Round, Heart or Star Shapes.