HUUM Chimney pipe adapter 4.5 inch to 6 inchAll HUUM wood burning sauna stoves are equipped with standard European exhaust piping that measures at 4. 5 inch (115 mm). This adapter is required for North American 6 inch (155 mm) piping conversion. A sauna stove chimney pipe adapter serves as a connector or transition piece, linking a wood stove or heating appliance to a chimney flue or vent pipe. Typically crafted from metal, such as stainless steel or galvanized steel, it securely fits around