50,000 Words (or Less)?
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. You forgot to attend class all semester except for that unfortunate sans clothing day. 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 refill of your favorite ballpoint pen.
Although it’s possible your ballpoint refill could be any of dozens, it’s likely you’ll need what’s often called a “Parker style” refill. It's so common to twist and click ballpoint pens it’s also called the “Standard International Ballpoint” refill. For the sticklers, this refill is properly an "International Organization for Standardization (ISO) G2" refill. It may appear the ISO can’t even get their initialism right, but they do know what they’re doing. You can trust the "ISO G2" will not fit the horde of "Pilot G2" pens you "forgot" to return to the office.
The name “Parker style” refers to the Parker Pen Company founded in 1888 in my hometown of Janesville, WI. Its distinctive slender neck accepts a spring while the plastic back end engages the pen transmission. When Parker’s patent for the refill expired, many brands began labeling their own “Parker style” refill. Each brand has their loyal following, but I prefer the Schmidt P900 refill. It’s a high quality ballpoint refill made with a stainless steel tip housing a tungsten carbide ball.
Another fairly common ballpoint refill is the “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.