The Waterbrush Pen is portable. Simply load water and it's ready to use! The Waterbrush Tip is flexible for either watercolor or calligraphy. It comes in size S, M, L and 3 Primary Water Color Paint Tubes. You can use the 3 primary colors to create any other color. You can mix colors using a palette or even a paper plate! This set is affordable and a perfect match for beginners!