Opal multiwall polycarbonate is a strutured polycarbonate sheet used in roofing applications and also as screens and partitions. It is a lightweight sheet available in thicknesses 16mm (Triplewall) amd 25mm (Multiwall). The sheet has a UV coating on one side - identified as the side with the branded lining. Once this lining is removed, this side of the sheet should face upwards. As standard, on all cut panels, the sheet channels are blown out with compressed air to remove cutting swarf and on finished panels, they are sealed with breather tape to prevent dirt or insects entering the sheet.