... 2.anti-corrosion, electric insulation. Fiberglass square tube (frp square tube) is the thermosetting plastic products combining the reinforced ... , polyester or vinyl ester etc. Fiberglass square tube (frp square tube) is a kind of composite material, but also ... by pultrusion. As other fiberglass profiles, fiberglass square tube (frp square tube) has the following characteristics: 1) high strength ...