Caran d'Ache Museum Professional Watercolor Leads are a highly pigmented, water-soluble 3.8 mm colored pencil lead that fit in the Caran d'Ache Fixpencil mechanical lead holder. They come in 18 colors and also in a B and 3B water soluable graphite. They offer exceptional lightfastness. Caran d'Ache Museum watercolor leads are instantly water soluable and lend themselves well to watercolor techniques however they also can be used for dry colored pencil techniques. They offer limitless blending possibilities and are suitable for all art supports (watercolor paper, art board, journals, canvas, bristol, etc.)