Pentel Mini Aquash Brush

This particular brand and this particular size of water brush are simply perfect.  I've never had a leak while storing a full brush with my watercolor pencils and the water flow is VERY easy to control. It's also an excellent tool for increasing the enjoyment of coloring books. 

From the company: Create a gorgeous watercolor masterpiece with this Aquash mini water brush from Pentel Arts. Just fill this mini brush with water and control the liquid flow to create a beautiful watercolor art. This water brush features a flattened barrel for a firm grip, while its durable medium tip promises a quick response for intricate lines or pools of water.

How to use:  

1. draw a picture with your Derwent Intense Pencils, then go over the drawing with a wet brush to blend the colors 

2. scribble down some color on the cover or inside of your Kraft-tex folder (it's a sturdy, magical non-paper substance), then use your wet brush to pick up the color and paint as if you were using a standard watercolor set

3. you can also fill the barrel of the brush with ink instead of water (great for doing fancy lettering)

PS. One final thing, in case it matters, "Pentel is the only writing instrument company to receive the Deming award for recognition of the highest standard of quality."