Small flat brush #4. Flat bristle tip is ideal for gel systems, smooth acrylic applications, large infill of long nails and long sized french extensions. Created with a gold round ferrule and sabel bristles fashioned with a slanted tip. Ideal for acrylic systems. Medicool's Kolinsky brushes are handmade in Germany by master craftsmen. They take the art of nail sculpting to a new level. The brush is developed specifically for the nail industry. Made with Kolinsky sable hair, the finest hair available, offering spectacular artificial nail-fashioning. Each brush has a gold plated ferrule and an acetone resistant mahogany finish handle.