Deluxe Water Brush has a fine tip and an internal twist syringe that you use to suck up water. To fill first twist the black knob anticlockwise on the back of the water pen to move the syringe all the way forward. Remove pen lid and dip in water and the twist the knob clockwise to suck up the desired amount of water. To use simply use the knob to control the amount of water you need on the brush tip. To store replace pen lid.