Series 839 Out-liner Mack Brushes, These brushes are made from pure brown Kazan Squirrel and Black Ox mixture hairs. They have a nickel ferrule and black and gold handles. The 839 is much softer than Mack's 838 out-liner and will carry more paint. These Out-liner brushes are used for outlining letters, for scroll work, and applicable sign work. The series 839 is suitable for most surfaces. It has a round ferrule and graduated hair lengths.