You have to hear the music. Reporter it may not looking exciting now , but this barge is spectacular. It will be lighting up your 4th of july. Reporter showing you how one of these turns into one of these. Thats the lift charge, black powder. Reporter that black powder sends this on onion shaped explosive in the air. When the shell gets to its proper height, that lights a bursting charge. Which sets off the lights in motion. The timing is everything. It all has to work for everything to be safe. Reporter the state of california only res one licensed technician and one assistant to be here. For the San Francisco fireworks, there will be 22 for the display. All will be set off electronically , designed by the this guy. I know the inventory of products that we have and what they do. From the top twin peaks you can see fire wooshgs from all over San Francisco bay. But until you you could not hear the music. But this year they have an app. It lets you listen to the music as it is in sink wi