There are two types of Paint Brush: Synthetic-bristle brushes- These are made of nylon, polyester or a mix of both & should be used in water based paint material. The best synthetic brushes have fuzzy-looking ends. Natural-bristle brushes- These are made of animal hair & should be used in oil based paint material. A quality natural-bristle brush is flagged, meaning it has split ends on the tips. Note- Short handle brushes are best for painting in narrow spaces. The short handle allows you to easily maneuver. If you have small hands, a short-handled brush may feel more comfortable.