This ducting is designed for various ventilation, circulation, and heating/cooling transfer applications. It features four-layer protection, making it more durable and resistant to leaks than single-layer designs. The internal layer is made of heavy-duty dual aluminium foil that is fire/flame resistant. Its outer layer utilizes dual PVC thermoplastic that protects the aluminium from cuts and tears while stopping leakage. Each duct tube is held together by ..