Able to cut a sharp line even in hot or humid conditions, ultra/pro extra-firm is the ideal choice for all thick or fast-drying paints and primers. It excels during exterior use. Made from 100% nylon and featuring an exclusive Wooster filament called NylonPlus™, it maintains rigidity, resists wear and cleans much more easily than brushes that use polyester to achieve extra stiffness. Look for the purple and black filament and the teal stamp on the handle.