Strong steel wire construction with taut wire loop top. 1/4″ threaded fitting to universal drain rod joint. Scrapes and brushes ceramic flue pipes and chimneys. Compatible with Silverline Drain Rod Sets. Brush diameter: 150mm. Strong steel wire construction with taut wire loop top. 1/4″ threaded fitting to universal drain rod joint. Scrapes and brushes ceramic flue pipes and chimneys. Compatible with Silverline Drain Rod Sets. Brush diameter: 150mm.