What are flexible Sun Tunnel� made of?

VELUX has improved upon the flexible tube technology used for years in the heating and air conditioning industries. Doing so, we've created a way to bend sunlight around attic obstructions to create the most cost effective and energy efficient skylight system available in the US. Our Flexible Sun Tunnel� Skylight consists of a double layer of metalized polyester film with a double inner layer of reinforced aluminum Sola-film and a highly reflective, ultraviolet-proof laminate. The dome on top is made of UV stabilized Grade-One acrylic (or polycarbonate where debris resistance is needed).