Security Chimneys™ adds the SM large-diameter chimney, featuring 2 inches of high-temperature blanket mineral insulation with solid-steel couplers, to its extensive product line. The SM large-diameter chimney was developed for custom masonry fireplace installations and masonry flue extensions. The chimney’s 2 inches of high-temperature blanket mineral insulation increase performance by keeping the flue hot and allowing a better draft. Contact: (800) 9-LENNOX or www.lennox.com.