I use fountain pens all the time. One of the rituals of filling a pen that seemed a bit bothersome to me is unscrewing and removing the section from the pen body to get to the converter filler twist knob. The annoyance usually comes if you haven't done a thorough job of cleaning the section after dipping it in the ink well for filling and you end up with ink all over your fingers after you screw the section back into the body of the pen. The pen below deals with that problem in two ways. First it has a long section, which, besides providing a longer grip area, means a cleaner more visible submersion in the ink well. The body has been modified to allow a cap over the cartridge converter end to be unscrewed for access to the filler twist knob. Now you don"t have to remove the section to clean and refill the cartridge converter.
This pen done in Rite of Spring Alumilite, cast by Bob Dupras, with a bright yellow alumilite finial, is a flush side pen 15.8mm (5/8") in diameter and 150 mm (5 15/16") long; your choice of #6 JoWo steel nib in Polished, Gold Dual tone, Ruthenium, or Black Oxide in EF, F, M, B, 1.1mm, 1.5mm depending on market availability. Price is $235 plus shipping. If interested, email me at email@example.com.
Along the same lines is a fountain pen done in Sea Seas Alumilite, cast by Bob Dupras, with silver alumilite trim. In addition to having silver finials on each end, this pen has a silver ring to highlight where to unscrew the end of the body to access the compact converter filler twist knob. The pen is cap dominant 16.6mm (11/16" OD) and the body is 15.8mm (approximately 5/8"). The body is tapered towards the from so that the cap actually screws over top of the body. The pen is 149mm (approximately 5 15/16") long; your choice of #6 JoWo steel nib in Polished, Gold Dual tone, Ruthenium, or Black Oxide in EF, F, M, B, 1.1mm, 1.5mm depending on market availability. Price is $255 plus shipping. If interested, email me at firstname.lastname@example.org.