Bristles are a blend of 3 components. Nylon for softness and ease of paint flow, Chinex for faster clean up with self-flagging tip, and polyester for stiffness retention. Extra length-out and thickness of the filament provides extra wear and paint holding capacity. Stainless steel ferrule and alderwood handle. Designed for all exterior paints and medium to heavy bodied interior flat paints. Professional quality paint brushes fashioned with a blend of nylox (dyed nylon) and polyester filaments. Only solid, round, tapered filaments are used in these brushes. Filaments are tipped and flagged by a special process to make them as close to naturally flagged bristles as possible. XL brushes are recommended for both interior and exterior painting with all paints. The stiffness retention from the polyester content makes these brushes highly effective for exterior painting in hot and humid conditions.