Fiberglass Skin Truck Body Insulated Box High-performance refrigerator truck body designed for optimal thermal insulation and durability. Material & Performance New type FRP (Fiberglass Reinforced Plastic) used for outer and inner skin Sandwich panel construction with extruded polystyrene foam core for superior thermal insulation Panels fixed to steel frame with high-strength adhesive and rivets for maximum durability Construction Fully enclosed structure with all panels