(On hold) This is a 1920s Parker Lucky Curve "ring top" button-filler fountain pen in black chased hard rubber (BCHR) with a 14k gold XXF full-flex nib. The pen has been restored, which included a complete disassembly, a gentle cleaning, an overhaul of the filling mechanism, ink flow adjustment, a nib tune-up, and a gentle polish with a soft cloth (by hand).
This is a superb example of the well-respected and highly collectible Parker Lucky Curve from the 1920s. It's in amazing condition, without any trace of wear or fading, which plagues the vast majority of BCHR pens from that era. The pen looks as good as new, and it would be a perfect specimen for the high-end collector. The imprint is strong.
The pen was designed specifically with Spencerian penmanship in mind. It's a classic "ring top," meant to be worn around one's neck, so it's a lightweight, compact pen when capped (4.5"). However, it converts to a full-size pen when posted (5.7"), as it is meant to be used that way. In terms of ergonomics, the pen resembles those of a well-designed dip pen holder, with a somewhat long, streamlined shape and great balance. It's extremely comfortable to hold, lightweight, and very pleasant to the touch. The button filling mechanism works flawlessly and holds a lot of ink.
The pen is a calligrapher's tool, a high-precision writing instrument, capable of producing beautiful penmanship. It was designed for a skilled hand, and will perform as well as any flexible pen of that era. I would rank it as a "full-flex," just shy of being a wet noodle, but it offers excellent flexibility, and fantastic snap-back. With light pressure, it writes an XXF line of about 0.3 mm (on my paper), and you can get the line even thinner if you use dry ink and dry paper. The nib excels at transitions between hairlines and swells, which is the cornerstone of Ornamental Penmanship. If you are new to flexible nibs, this pen is probably not for you, unless you're willing to learn its dynamics and try to write with a light hand. The best news is this pen had not been used much in the past, if at all, which means the nib is free from any (invisible) damage that many vintage flex nibs develop over time (due to using excessive pressure). The tipping material is ample and of perfect geometry.