Brushes are a compact, low profile design. The benefits of this design are a brush that follows chimney and flue contours, a brush that will easily reverse direction in the flue for easier cleaning, a brush that will easily negotiate angles and bends up to 90, and a brush that results in a more thorough cleaning with less effort. 1/4" NPT. No. 30600: 6" No. 30800: 8"