If you like to carry your pen in a pants pocket, then you know it takes just the right one to fit comfortably without poking, bending or breaking, or leaking.
Preferably, it needs to be a pen with smooth edges, rounded on one or both ends, and equipped with a sturdy clip. It has to be made of metal or tough plastic. The ink cartridge needs to be reliable. And, of course, it has to be able to write well.
Here are a few pens that fit most or all of those criteria.
SureFire EWP-02 – Recommended by outdoorsmen, the main advantages of this 5-inch pen lie in the hardened aluminum barrel and the pocket clip described by the maker as "virtually indestructible." The SureFire is not going to break in your pocket, no matter how strenuous the activity, and will stay where you clipped it. However, it's a retractable, so one end of the pen is pointed, which means you could poke yourself if you carry the pen loose in your pocket, rather than clipped.
USUS io Ballpoint – This pen has no clip, but that's OK because its design is so smooth, you can easily carry it loose in your pocket with worrying about it catching or poking. And since the retractable, which operates by way of a set of magnets, is made from aircraft aluminum, it isn't likely to break either. Accepts standard Parker refills for smooth writing.
Lamy Pico – The ultimate pocket pen, the Pico is smooth and rounded when closed, measuring just over 3 ½ inches in length. It fits into any pocket comfortably. Made of rugged plastic. Unfortunately for those who like to pocket clip their pens, the Pico does not have a clip. Writes reasonably well, although not as well as some ballpoints.
Fisher Bullet Space Pen – A classic pen to drop in your pocket and go without worries. The smooth barrel and rounded ends of the pen when capped ensures that it will slip easily into your pocket and rest there comfortably. No concerns about breakage, as the pen is made from brass. And the Fisher ballpoint ink cartridge is famous for being able to write under even the most extreme conditions.