... metric M6 brush thread NYLONG TUBE BRUSH FOR CONDENSER, CHILLER, COOLING TOWER, EVAPORATOR, ABSORPTION MACHINE, HEAT-EXCHANGER TUBES CLEANINGSpecifications: ... Available for tube sizes 1/4"-1" Cleaning Diameter( ... 30.6315.90.6917.50.8819.10.8120.60.8822.20.9423.81.0025.4 Nylon Tube Brush (round cleaning ...