Purdy Dale Elite Paintbrush Cutting In 1" can be used on both interior and exterior surfaces. It can be used with all types of paints including undercoats, enamels, gloss, varnishes and stains. The Elite brush features stiff brush filaments that are a blend of DuPont, Chinex and Orel Polyester solid round tapered filaments. These allow for smoother application and can also be cleaned easily. The angular brush allows for easier cutting in and precision and is used for more intricate and detailed work.