The tubes may be circular,square,trapezoidal or other cross-section,as well as truncated cones or pyramids,as well as specially reinforced to obtain a high flexural strength (tube-in-tube). The inner surface can be smooth or threaded even during winding -without interruption of the valve. The composite can contain inserts(eg.threaded) of another material(eg.metal).
The tubes can be ”sandwiched” in which different materials alternate(eg.non-composite inner layer for heat or corrosion resistance and an outer composite layer for mechanical strength).
The tubes are suitable for parts and products of energy-low-oil circuit breakers,high voltage transformers and inductors , stepping voltage regulators, rods of high voltage and indicator rods,grounding ,various insulators , insulating ladders and stools,details of electrical equipment,tubes for high-frequency welding,details for antenna equipment for high frequency,structures of the trolley electricity,piping and nozzles for normal and chemically active fluids and bulk materials, ducts,rollers for conveyor belts, railway and road barries,pylons,poles,oars,ladders for boats and cutters.