The Inart Wide 4mm Water Brush with Reservoir (110799101) features the same integrated reservoir system in the handle as the other widths in the range, releasing water via a push button whenever the brush body is gently squeezed. The wide 4mm tip, the largest in the range, is ideal for filling larger areas with watercolor or gouache washes more quickly than would be possible with the finer tips in the same line, saving time on large backgrounds. The flexible and durable nylon fiber bristles maintain their original shape even after several uses, and the reservoir remains closed when the button is not pressed, preventing leaks inside your backpack. It is ideal for those who paint backgrounds, skies, or large areas of color outdoors and prefer not to carry a separate water cup.