Carpenter Space Pen Being able to write across wet wood without your pen skipping. The Carpenter Space Pen utilizes revolutionary technology to make sure it performs in a variety of situations. Upside down, its side, through water, or in extreme temperatures, this Space Pen contains a sealed pressurized refill (SPR) that will perform. Even if you aren't a space explorer, the Fisher Space Pen can guarantee you can mark any worksite surfaces you encounter without a second thought. Includes Scale (CM and Inches), Magnetic strip, Drywall gauge, Level, Plumb, Cross Level. Feature guide inside. Details : Fisher Space Pens Cartridge is sealed & pressurized at nearly 35 pounds per square inch Tungsten carbide ball Writes from -30 to +250 degrees F Writes:- On wet surfaces, On photographs, Through grease, Underwater, At any angle, Upside down Cartridge : Pressurized 35 PSI Point : Medium