This Fisher Space Pen is the ultimate writing companion. You should never leave home without a pen. With the small 3-11/16 inch closed length of the space pen, there is no reason not to have a pen in your pocket at all times. I keep one in my right front pants pocket with my loose change and I never know its there unless I need it. Opens to 5-3/8 inch which is standard pen length. Uses pressurized ink cartages, so you can write upside down, underwater and almost any place you may want to take a note.