Fisher Space Pen Pocket Tec Space Pen, Orange (PT/O) Writes Underwater, Upside down & at any angle, over Grease, 3x longer than an average pen. Also writes in extreme temperatures (-30 Degree to 205 Degree). Writes in extreme temperatures from -30F to 250F Each Fisher Space Pen is precision assembled, hand tested, and carries a lifetime guarantee against all manufacturing defects