The Secure Stack Pro Series, Models SCL, CAX1, CIX1, CIX2, CIX4 and CIX3Z venting systems are designed to offer the ultimate in installation convenience and versatility for a variety of applications. Certified for commercial chimney and diesel exhaust applications, they are constructed of thick-gauge material for the inner pipe that provides a strong and rigid assembly. Featuring a self-centering flue extension design that significantly simplifies and accelerates the installation process.