Stabilo Write-4-All fine-tip, permanent marker pens are suitable for most surfaces including glass, plastic, photos, ceramic, foil, metal and more. They are reliable under extreme conditions such as cold, heat or rain. The odorless, waterproof, alcohol-based, non-corrosive ink dries quickly and is light- and frost-resistant. The pens feature a .7mm fine tip, long cap-off time without dry-out and a ventilated cap. Stabilo has tested these pens on over 1000 surfaces!