1. UV prevent. 2.Easy to ship and install. 3.Corrosion resistant,higher strength. We use Vinylester resin to manufacture,there will be topcoating on the surface which can prevent UV.FRP ductworks are with the character of corrosion resistant,higher strength,easy to ship and instal.They are widely used for exhaust piping,and there are flanges,flat butt as connecting ways.