Okay, so I live in Nebraska. Where I live there are farms and cattle everywhere. The cows actually do outnumber the people. So if you have ever been to a dairy farm.... you can't help but think this pen looks like a cow with one utter. Anyway, its a bulb filler with a 14mm body and 17 mm cap. The pen is 6 inches long capped. I got that whole length thing figured out since the last one. The pen body is 5 1/2" long. As near as my terrible math tells me the pen holds about 6.5ml of ink which is about 5 times as much as a converter. I would love to hear what everyone thinks... moo, because all I can.... mooo, think about... mooo, is a cow.