COPIC ink is an alcohol-based substance that does not dissolve and works well with watercolors and colored pencils. COPIC Classic, Sketch, Ciao and Wide markers are refillable by using this fast-drying, permanent and non-toxic ink. To refill the markers, match the color number on the marker with the corresponding ink color number. This 12ml ink will be able to refill all Copic markers approximately 3.5-9 times, depending on the marker type. Empty Bottle is available for blending and creating custom colors.