"Due Monday 50,000 Words on What You Did Last Summer," an essay surely to evoke other unpleasant dreams I still have about school. You know the ones...you lose the combination to your locker that you can’t even find, or you forgot to attend class all semester except for those unfortunate sans clothing days. Luckily, 50,000 words or less is just a marginally useful estimate of how many words a “typical” ballpoint can write before running dry. But let’s assume your fascinating disquisition does indeed exhaust the once boundless promise of your favorite ballpoint pen. Which of the many International Organization for Standardization (ISO) recognized refills do you need? Despite your doubts that the acronym should be IOS, not ISO, you can rest assured I know what I'm talking about most of the time.
The first refill needed for all my ballpoint click pens and many of my ballpoint twist pens is known as an ISO G2. It's often just referred to as "Parker-style" to avoid confusion with an incompatible Pilot G2 pen refill. The "Parker style" refill has a close association obviously to the Parker Pen Company founded in 1888 in my hometown of Janesville, Wisconsin. This refill holds a generous supply of ink available in at least seven colors depending on tip size. When Parker's patent for the refill expired, many brands began labeling their own "Parker-style" refill. Some of the many brand names you may encounter include Parker, Pelikan, Monteverde, Schmidt, and Sheaffer. Although its dimensions vary slightly by manufacturer, its shape is distinctive whether metal or plastic. You'll notice it has a wider barrel that thins into a neck to accept a spring. The opposite end is generally plastic and notched to engage with the pen transmission.
Each brand has their loyal following, but I prefer the Schmidt P900 refill from Schmidt Technology of Germany. It's a high-quality ballpoint refill made with a stainless-steel barrel and tip housing a tungsten carbide ball.
Another fairly common ballpoint pen refill is the C1 or “Cross style” refill. It’s only found in twist ballpoint pens. This refill has a very distinctive elongated shape with a threaded plastic back end that screws into the pen transmission. This eliminates an internal spring prone to be lost and then found by the vacuum cleaner. Some of the many brands you may encounter are Cross, Monteverde, Sheaffer, and Schneider.