Environmentally Friendly! Permanent! Safe to use! Haps-free, xylene-free, alcohol based paint. An effective industrial grade alternative to our xylene based permanent paint pens. Permanent and waterproof. Quick drying. Fade & abrasion resistant. Works on metal, any non-porous surface, and even most porous surfaces. Suitable for indoor and outdoor use. Mighty X Marker paints are also available in 4oz, 6oz, and 1gal containers.