This 5 inch diameter brush is produced to professional standards Bristle length is one inch and the bristles have are stiff Steel shaft has been engineered to resist spinning out of the block Save time and effort cleaning and scrubbing brick, concrete, and stone 4 5 inch diameter drill powered scrubbing brush features nylon bristles, rugged construction, and a dual purpose stainless steel shaft. This brush fits securely in battery powered drills. Red stiff bristles are designed for heavy duty scrubbing and tough stains on garage floors, brick and concrete.