Unlike ordinary ball pens which rely on gravity to feed ink, the replaceable Space Pen cartridge is pressurized.
At nearly 50 pounds per square inch, ink is continuously fed to the tungsten carbide ball, allowing the user to write at any angle, even upside down!
The new visco-elastic ink, with a consistency similar to that of very thick rubber cement, flows as a result of the shearing action of the rolling ball in its socket. This shearing action liquifies the solid gel thixotropic ink, allowing the pen to write smoothly and dependably on most surfaces and even under water!
Operating temperatures range from -50F to 250F
Evaporation, wasted ink and back leakage are eliminated
Shelf-life is increased to an estimated 100 years This is an all metal, retractable Red, White and Blue Space Pen.
This pen contains a PR4F Black Ink, Fine Point Refill.