The Umbria liner is great for creating lines with crisp edges. The long hairs can hold a lot of color for continuous strokes. Princeton 6250 series Umbria Brushes are perfect for oil and acrylic paints, but also work well with gouache and watercolor. The synthetic bristles are not as stiff as natural bristle, but have a more firm response than sable or white synthetic. An excellent choice for heavy body paints. The Velvetouch silicone sealed handle is comfortable to the touch and allows for smooth handling.