WRITES UPSIDE DOWNPressurized ink cartridge performs in temperatures from -30F to 250F, under water (down to 35 ft), and at any angle.INK WON'T SKIPProprietary ink and delivery system used exclusively in Rite in the Rain Pens will write without skipping in extremely wet conditions.WRITES THROUGH…Permanent ink writes through water, sweat, grease, and mud without clumping or smearing.