Feberglass tubes is made of fiber and resin, used to display shell fireworks, size to 16 inch, can be used for hundreds of times. Here is brief process of production: 1, put the inner liner on the machine tubes; 2, fiber on inner liner and sametime pour resin on fibers which the machine is spinning to make it round; 3, another layer of fiber and resin to make the thinkness is enough; 4, cover finished wet tubes with plastic paper, to make it clean in dry process; 5, after it is dried, cut them into named sizes. Some photo for reference: cutting into named sizes, the worker make the lines to show the size to himself