The Inart Medium 3mm Water Brush with Reservoir (110799100) balances precision for details with quick coverage of larger areas, making it the most versatile size in the range for everyday watercolor or gouache painting outdoors. Like the other widths in the line, it has an integrated reservoir in the handle that eliminates the need for a separate water container, releasing the liquid via a push button whenever the brush body is gently squeezed. The flexible and durable nylon fiber bristles maintain their original shape even after several uses, and the reservoir remains closed when not pressed, preventing leaks inside your backpack. It is ideal for those looking for a single water brush for most painting situations while traveling or outdoors.