By the fan: Fire-retardant can issue polystyrene , one kind of the resin . This material is fire-retardant , heat-resisting , light, the hydroscopicity is little , insulating and having very good elasticity and rigidity . Fan burst: Glass fibre reinforced plastic , strengthen plastics with glass fibre one. The light and hard , mechanical intensity of the quality can be on par with steel , not conduct , able to bear water , corrosion-resistant,