The walls of the trailer are lined with Rockwool sheets. These consist of rock wool fibres that are bound together into water-repellent panels, after treatment with a thermosetting binder. The panels are then finished with an extra layer of aluminium, which gives insulated trailers a characteristic appearance. The certified plates are 70 mm thick and easily deliver the required thermal resistance (R < 1.65 m2 K/W). It is advisable to have the entire trailer covered when transporting goods over long distances. Covering the floor and side walls with insulation may be sufficient for shorter distances.