These super colourful medium size 41cm Northstar Number 0 foil mylar letter balloons are best way to celebrate a milestone birthday! Inflate these balloons with helium to have them float or with air to not have them float and attach them to the wall. These massive balloons are great for bouquets, photo backdrops, on the top of balloon columns, design them into the top of balloon arches and more. Add colour coordinating mylars and latex balloons for the ultimate balloon bouquet! This balloon includes a self-sealing valve, preventing the gas from escaping after it's inflated. Balloon arrives uninflated.