These Promarkers are alcohol-based, non-toxic permanent ink markers. The professional quality dyes used provide for a smooth, streak-free finish and can be applied liberally to paper without damaging the surface. Great to use on a wide range of other surfaces, including glass, acetate, plastic, metal, textiles and more! The translucent colors can be blended for an almost unlimited palette, while single colors can be layered for added depth and shade. Each marker has twin tips; the fine nib for precise coloring and details and the broad nib for large color fills. Certified non-toxic and conform to standard ASTM D-423.