The E&J Generation X Rat Tail Angle Sash Brush is a professional grade brush with a stainless steel, square ferrule and sealed birch, square rat tail handle. 100% Chinex Bristle is a firmer filament, that is great for Ceramic & Waterborne paints. Used on walls and trim. The razor edge allows for perfect cutting in. Designed to hold more paint and allow for better release of paint. Cleans out quickly.