Our professional grade wire chimney brush is top choice among do-it-yourselfers and chimney sweeps. These high-quality brushes are made with hundreds of 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 (twice as many) 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. Specifications: Dimensions: 7'' square x 7'' long brush body; 9 1/2'' overall length 3/8" Male NPT 3/4'' loop for rope cleaning Professional grade chimney brush Oil tempered, 22-ga. steel bristles Greater number of bristles as compared to standard homeowner grade brushes Important Note: The tolerance on the brush body and overall length for all brushes is + - 1/2''