Non-permanent acrylic markers with water-based, saturated colors and a hard tip. You can use them on stone, paper, canvas, glass, porcelain, plastic, wood, cardboard, and metal. The marker is not indelible, so it's easy to clean skin with a bit of soapy water. However, the paints are fairly water-resistant when dry, which is a huge advantage if you're painting on stones. * The marker has a line width of 4mm. * Important: Store the marker lying down and closed with the cap. However, if the tip dries, you can dab it on paper until the ink flows back inside. * Set of 24 colors.