Ultra-high production makes Ultra/Pro Firm the best-selling blend and a favorite for over 25 years. Featuring a mix of nylon and polyester, it's truly an all-purpose professional brush for use in acrylics, latex, or enamels, indoors and out. With fantastic coverage and masterful cut-in control, it saves painters time wherever a firm brush is needed. Look for the purple and sable brown filament and the maroon stamp on the handle.Ultra/Pro Professional Flat Sash Paint Brush, 3 x 11/16 Inch, 3-3/16 Inch Trim Chisel, Purple Nylon/Sable Polyester