Fisher Space Telescoping Pens
The Fisher Telescoping Space Pen, with its pressurized refill writes under water, upside down, on greasy surfaces and in very cold or hot climates.
This telescoping model goes from 3.90'' closed to 4.75'' when open to offer a longer surface for holding it when writing. To open and close it you just push and pull. When the pen is collapsed the writing tip will be hidden and appears when you extend it so you can only write in the extended configuration and there is no cap.