Polyester net is mainly used for the squeezing out the air bubbles. Normally is used after the pipe liner is manufactured first 1 to 1,5mm of pipe wall. Then the net is used on the end of manufacturing process, when the pipe wall is finished. In this last layer the polyester net gives also another result. Since the polyester net can be tensioned a lot, the effect of the applying the net is that the resin is squeezed on the surface of the pipe, which gives to the pipe surface, uniformity, smoothness and shines. On the continuous winders that use polyester net in the last layer of the pipe wall, because without this net the pipe surface is very uneven and the fibers stick out from the pipe.