Tunnel Liner is a highly flexible polyethylene geomembrane specially designed for high-performance tunnel lining applications. Solmax (previously GSE) Tunnel Liner consists of a black core layer and two white outer layers, which greatly facilitates visual inspection and is available in two fire resistance grades (B1 and B2). It is suitable for both new designs and retrofit installations. Solmax (previously GSE) Tunnel Liner provides a unique combination of security, sealing integrity, and installation efficiency.