Fisher Backpacker Space Pen, Red (BP/R) 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). Each Fisher Space Pen is precision assembled, hand tested, and carries a lifetime guarantee against all manufacturing defects Aluminium and Brass construction 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). Aluminium and Brass construction