Our professional grade wire chimney brush features hand-made construction with oil tempered, 22-ga. steel bristles. The spindle has a 3/4" loop on one end and 3/8" Male NPT Thread on the other. Each bristle is individually placed on the spindle in a two-on-two pattern, and then positively locked as the spindle is twisted into a double-spiral configuration.Our professional grade brush will make cleaning chimney flues easier due the the greater number of bristles as compared to standard homeowner grade brushes.The 5SB-36048M 3/8" NPT brush rods will mate to the threads on this brush. You can also use the 5SB-30624M brush rods and a 5SB-36352M 1/4" NPT x 3/8" NPT adapter.