These POSCA Paint Markers are made using a non-toxic, water-based formula that produces dense, vibrant colours on a variety of surfaces. The markers are permanent on most porous surfaces and are removable on glass. -The markers have a medium bullet tip that measures 2.5 mm. -They are suitable for use on a variety of surfaces including paper, metal, glass, wood, and plastic. -The ink is vibrant, fade-resistant, and quick drying. -The markers are acid-free and non-toxic for your peace of mind. - Colours included in this pack are  Metallic Blue, Metallic Pink, Metallic Red and Metallic Green.