Astria 6-inch Wood Burning Storm Collar 6SPSCAstria 6 inch Wood Burning Storm Collar 6SPSC Product Details What is the function of the Astria 6 inch Wood Burning Storm Collar in a wood burning chimney system, and how does it help prevent leaks and maintain chimney performance? The Astria 6 inch Wood Burning Storm Collar is designed to seal the area where the chimney pipe meets the roof. Its primary function is to prevent water from leaking into the chimney system, which could cause damage or