The Rite in the Rain All-Weather Bullet Pen functions in extreme conditions. The pressurized ink cartridge writes upside down and through moisture without smearing or washing off.FeaturesWrites upside downPocket Clip Pressurized ink cartridge performs in temperatures from -30F to 250F, under water (up to 35 ft), and at any angleProprietary ink and delivery system used exclusively in Rite in the Rain Pens will write without skipping in extremely wet conditionsPermanent ink writes through water, sweat, grease, and mud without clumping or smearing