20" Mylar Helium Blue Star

20" Mylar balloons are a foil type of balloon, It is not used for release because they could get caught up in electrical lines. 

They are expand in the heat and deflate in a cooler enviornment  so may be delivered a little deflated until the balloon adjusts to the new enviornment, then they will puff up.

Mylar balloons should last 2 days but depending on the size and make they can last up to 7 days.