Foil balloon (also called mylars) are self sealing balloons.  They are great for balloon bouquets and decorating.  These are two sided with a coordinating or identical image on back.  Foil balloons stay inflated for days and weeks.  Use a foil tip inflator for best results.  Filling these balloons with the incorrect tip (like the black rubber tip) uses more force and can cause the balloon to pop or create a leak in the seam.