This Rectangular Flat Wire Brush Head is made by Professional"s Choice, The brush head measures 12 inches by 16 inches, The connector fitting is a plated, double swaged 3/8 inch NPT type thread, The Polypropylene bristles are designed to remove soot from gas, oil and coal flues without deteriorating like steel, The brush heads are commercial quality suitable for professional use by chimney cleaning services, The 12-Inch x 16-Inch Rectangular Professional"s Choice poly Brush Head outlast other similar brush heads, Professional"s Choice chimney brush head with a 12-inch x 16-inch rectangular shape, Features a plated, double swaged 3/8-inch thread fitting of the traditional-course NPT-type thread, Polypropylene bristles are designed for removing soot from fossil fuels in coal, oil or gas flues where the acids may deteriorate steel bristles, Brush head has a has a single spiral 0, 177 dia, spindle design, The 0, 075-inch poly filaments are 7 inches of fill, Professional"s Choice brushes are moderately priced chimney brushes that are rugged enough to stand the everyday demands of the busy sweep, SKU: RTLD215