Double ends allow for large surface scrubbing on one end and precision cleaning with the smaller end. Includes brushes with different bristle material for varying levels of aggressiveness when cleaning:nylon, bronze and stainless steel. The nylon brushes are the least aggressive, meet Mil. Spec. and are safe for everyday use. Recommended for use on virtually any surface including wood surfaces. The Blue Nylon Brush features stiff bristles that allow for a more aggressive clean.