Chamber Safe is a UL Listed, high performance, refractory parging material, designed to strengthen, streamline,and restore the critical smoke chamber area in masonry chimneys. Preferred by chimney professionals, ChamberSafe smooths jagged, corbelled walls typically found in the smoke chamber, and creates a smooth transitionbetween the smoke chamber and flue liner. Chamber Safe is the ideal choice for improving the flow or draft of thefireplace! The unique insulating properties of our Chamber Safe material improves the safety of the chimney byreducing radiant heat transfer through the smoke chamber. This product is non-water soluble.