A product which came about from the need to reduce the number of "zippers" (tearing of airframes by shock-cords at the moment of deployment), by spreading the load which shock-cords place on the lip of airframes upon opening of the parachute. If your rocket is traveling in any kind of ballistic arc or is experiencing a late deployment, odds are you will experience a "zipper". The Fireball is a foam ball covered by Kevlar sock for ejection gas heat protection with a short length of Kevlar cord going through the middle. One end of the cord is attached to the rocket, the other has a sewn loop which your main shock-cord is attached to. you must always utilize additional heat protection for the FireBall as the Kevlar sock over it is not sufficient. You need to utilize a Kevlar chute pad, cellulose wadding or both for this purpose. As an aside, if you should get an airframe zipper, the best way to fix it follows these steps: (a) clear any rough edges (b) insert a proper sized coupler WITH wax paper on the exterior into the problem area. Fill the problem area with epoxy and filler and then wrap a second piece of wax paper or mylar around the exterior of the affected airframe, leaving the coupler in place. (c) After curing, remove the exterior wrapping and interior coupler/wax paper, sand and fill in low or high spots.