... density polyethylene engineering plastic as its protect layer,which make duct rodder cover sliding on surface,durable,corrosion resistant and has ... performance,which make them safe for using in cable occupied duct. High Density polyethylene(grade: for insulating and jacketing of ... ,250,300,350,400,450,500 meters for choice. Material Fiberglass (inner) and high density polytgtkebe(outer) Density 1.9gr/ ...