Staedtler Pigment liner sketch pens aren't just for drafting anymore. 

• Long metal tip, great for using with rulers or templates
• Waterproof, light fast and indelible pigment ink
• Erasable when used on drafting film
• Available in several line widths
• DRY SAFE - can be left uncapped for upto 18 hours without drying out

Staedtler "where innovation meets tradition" are one of the first pencil manufacturers in the world, dating back to 1835.  Records in Nuremburg, Germany show a Freidrich Staedtler as pencil maker as early as 1665.  All of their woodcase pencils are certified PEFC or FSC for responsible use of raw wood materials.

They are not just known for pencils, but of many other writing, drafting and art products as well.  When you see the Mars head symbol, you know you are getting a quality product.