Features - DMTflex composite-type flexible elements consist of multiple layer of high temperature fabrics, thermal insulation and an external cover of materials dictated by the operating conditions and external atmosphere around the expansion joint location. The addition of a PFE film laminated fiberglass vapor barrier and extra rein-forcing piles are also incorporated in this construction if there is a cycling of the flue gas through the dew point. Structure - Multi-layer expansion joint - Outer cover material - Gas sealing foil - Temperature-resistant fabrics - Insulating materials