Mr. Gasket Complete Engine Cleaning Brush Kits include nine assorted brushes to get at hard-to-reach grime anywhere on your engine or transmission. Ranging in diameter from a quarter-inch to a full five inches, they're made from stiff-bristle nylon that won't soften or melt when subjected to harsh petrochemicals. The heavy-gauge twisted steel wire handles bend enough to get around corners and through stubborn galleys without breaking, and they end in a loop for easy hanging and storage.