This is a derivative of my 2 Liter bottle to 1/4 NPT adapter with reasonably sturdy little fins. The adapter is designed to let you quickly turn an ordinary house hold pop (soda) bottle into a projectile by adding water and air pressure. the 1/4 NPT quick disconnect gives you a simple and easy way to add air pressure and also works as a launch mechanism when you release the collar.Please see the parent of this item for instructions, that way I can just make corrections there as I intend to make several derivatives.