Buy Mack Brush Series 444 "The Virus" here. The Virus Series 444 script brush is a specially blended golden taklon. This recommended design by the industry leaders is perfect for script and scroll work. One of the sign industries most exciting and innovative new brushes affectionately called "The Virus" , other terms for this kind of brush include , Lettering brushes, script brushes, outliner script brush, detail script brush, mack brush script liner and pinstripe script liner. listed below!