Cloudbusters are balloons generally used for advertising to draw attention to the physical location of businesses who fly them very high above stores, flea markets, warehouses. 

You can use a line or a pennant line depending on how much attention you would like to draw. A heavy-duty nylon tether line is recommended if you are not using a pennant.

The pennant line is a line with triangular flags on it. You can see which line and pennant go with which different sized cloudbuster by looking at the title. There is more lift on an 8-foot balloon than a 5.5-foot balloon, so you need to have a stronger line. 

It is also important you don't switch lines. If you are using the 5.5-foot line on an 8-foot balloon it's going to be too heavy and it will affect the flying time of the balloon. You can see which line and pennant go with which size cloudbuster by looking at the title. 

In order to ensure the longest flying time–  the balloon should be measured and sized to the size that is outlined on the packaging. In this case 5.5 feet or 8 feet depending on which is chosen.