Engine Oil Gallery Cleaning Brush Kit Set Of 12 BrushesFeature & Fitment It's Important To Have A Clean Block Especially In Critical Hard To Get At Areas Of The Oiling System Each Brush Is Designed For A Specific Purpose; There Are Two Each Of The Oil Gallery Brushes Since They Get The Most Wear Can Also Be Used On Crankshaft Oil Holes, Cylinder Heads, Etc; Bristles Are Made Of Nylon Which Cleans As Well As Wire But Does Not Scratch Sets Of 12 Brushes Package 2 x 1 4"Dia. 2" Long 10" Handle 2 x 5 16"Dia.