WARNING - Do not use on damaged paint surfaces (including paint oxidation and clear coat peeling) as the ink may not remove completely from surfaces with damage. Do not leave on car hood in direct sunlight for more than a couple days (especially on very hot summer days).The Auto Writer is designed for sign writing on non-porous vehicle surfaces such as drawing on painted car doors and windshields. What makes our paint markers unique is they are water resistant to showers however it is easy to remove the ink from surfaces with a wet cloth, this makes writing your glass paint slogans and announcements on a regular basis super fun and easy. The formulation is water based and with no solvents. How to Apply: Once you have a clean non-porous undamaged surface you simply shake the marker then pump the nib on a flat surface such as a piece of paper or cardboard repeatedly to activate. The ink will dry within a minute of use. Wet wipe erase with a wet cloth. Suitable for indoor and outdoor use as Auto Writer can be used on mirrors and any glass surface in your home too. Resistant to showers. Valve activated to control ink flow. For use on car body panels (undamaged) and windscreens. Water based & non - toxic.