The Staedtler Permanent Universal Pen F is a fine tipped pen designed for use on nearly any type of surface. The ink is smudge proof and waterproof, making it very durable. A PP barrel and cap shield the ink from drying when not in use, however dry safe technology allows the pen to remain moist, even when it's left uncapped for several days. The pen also has automatic pressure equalization technology, making it safe for use on airplanes without fear of leaks. Order this refillable permanent pen today!