Review on Pack of 6 Jumbo 40-Inch Gold Metallic Foil Letter Mylar Balloon Banner Garland for Baptism, Christening, Baby Shower, Gender Reveal, Sweet Sixteen, or Birthday Party Supplies - Ideal for Girl or Boy Celebration by Brandon Harding

I bought the 40 inch gold. Filled with helium (expensive!). I rented a helium tank for this occasion. The bottle opening fits snugly into the spout of the tank. I just had to pinch the opening to close it once inflated. If you fill her with helium, it becomes very annoying to keep filling her after she's about half full, as she then starts to float and someone has to hold her. It's definitely a job for two. Also, you don't want it floating all the way to the ceiling! You should also have the weight and rope handy after you've finished inflating! Be careful not to inflate too much. If it's full and looking good, stop this second. Wrinkles are part of the design and will never completely go away no matter how much you fill the balloon. The air is held for a very long time. At least with helium. So if you want to blow it up the night before I would say go for it. A week after the shower, the balloon was still 90% inflated. This and several other balloons in the room looked amazing!