A vacuum filler pen with the ink capacity of an eyedropper filler!
I like pens with large ink reservoirs, because more is better, especially if I'm away from my ink stash. Eyedropper fillers offer the highest ink capacity, but...if you don't have a way to shut off ink flow between reservoir and nib unit, you run into "burping" issues, which can get very messy, especially if you can't see if there's ink in the cap. The solution was either a vac filler, or a "Japanese eyedropper", both of which have a plug attached to a rod that can be screwed into the opening between ink chamber and nib unit, sealing it off. My Opus 88 and Visconti Homo Sapiens have a total ink capacity of around 3.5ml. The Monster G5 has an ink capacity of 7ml. That's like 10 Standard International Short cartridges! That means most casual users might fill their Monster 2-3 times per year. Using a Fine nib, one complete fill lets you write 450 A4 pages, or about 54,000 words. Hopefully, you REALLY LOVE the ink you filled it with, because you'll be looking at that ink for a long, long time!
But not only is the ink capacity huge, the pen itself is pretty amazing, as well. The Kraken filling system, a clever variety of a vac filler system (with an improved shut off valve) that prioritizes ink capacity, is virtually unparalleled in modern pens currently on the market. The Ultem (or clear Acrylic) body of the pen is polished to crystal clarity, the metal is highly corrosion resistant titanium, and the #8 steel nib is smooth as glass.
I'm cheap, and boring, so I do most of my fountain pen writing on plain copier paper, which allows the ink to spread out, letting a Fine nib make a line like a Medium nib. I also like to use Pelikan 4001 Königsblau, because I got a good deal on the 1,000ml bottle of ink from my favorite online seller. The combination of cheap(er) paper and ink pairs really well with the Monster's #8 nib and feed; my Fine nib makes a line comparable to a Japanese Medium nib, while keeping the color richly saturated. Using standard European 5mm quad ruled paper, the nib writes thin enough to be perfectly legible. I do have to write a bit slower, though, because the generous ink flow also means longer drying times, and writing too quickly can cause smearing issue. That's a me-problem, not a pen-problem.
The nib itself is stiff, but very smooth, meeting or exceeding the smoothness of all of my JoWo #6 steel nibs. In my opinion, the combination of nib and feed make this one of the best general purpose pens you can buy, because it will work reliably on a wide variety of paper, and a wide variety of inks. As with all demonstrator type pens, avoid "high maintenance" inks, like permanent/document/waterproof inks (and Baystate Blue), because unless you're a professional writer/author, that ink is going to stay in your pen for at least a month, and your pretty clear tank may become stained permanently.

The Copper Sentry is one of the heaviest pens on the market. However, I find that hand fatigue is hastened more by grip section than the pen's overall weight. Moreover, the pen is back-weighted, with the center of gravity resting on the web of your hand between thumb and index finger, which makes the business end of the pen much easier to move across the page. The grip section of the pen is made from PVD coated stainless steel, and tapers from around 13mm to 11.5mm in diameter, making it ideal for a large pen.
The finish is flawless and free of blemishes and tarnish, but it will accumulate micro-scratches over time. However, unlike coated or painted pens, these scratches will me much less noticeable, because there is no bright shiny metal to contrast with the colored coating.
The nib is JoWo #6 compatible, meaning that the nib unit has the same type and size of threads as a standard JoWo nib unit, and you can most likely put a different type of JoWo #6 type nib into the nib unit. However, if you do that, be extremely cautious when putting the cap back on your modified pen; if the new nib sticks out a bit further than the original nib, there's a chance that the inside of the cap may touch/damage/destroy your new nib. And I can not tell the difference in performance between the Gravitas nib and a "genuine" JoWo #6 steel nib. The nib is smooth, with barely the hint of feedback, and ink flow is absolutely perfect, even with Pelikan 4001 Königsblau ink, which is dry enough to cause ink flow problems in some of my other pens.
The clip...is still not present on Gravitas fountain pens. And there is no roll-stop, either. So...that does limit your options in how you transport your pen, and the handy black single pen zippered pouch the pen is delivered in may become your default storage and carry option. If you're considering a pen sleeve, get one with a folding flap, to prevent the pen from sliding out of the sleeve.
Last item: ink capacity. Gravitas pens are designed for Standard International cartridges and converters. Converters hold 0.5ml, Standard International Short cartridges hold 0.7ml, and Standard International Long cartridges about 1.2ml - 1.4ml. You can "refill" cartridges with bottled ink using a blunt tip ink syringe, which gives you almost as much ink capacity as a standard piston filler pen. With a little practice, you can refill your cartridges without making (much of) a mess ;-), but keep a paper towel handy, just in case.

Great service - from management of expectations, communication, delivery speed and quality packaging...and the friendly handwritten notice by Ema that did not go unnoticed.
Thank you!

This is a nice upgrade to the original Aluminium body / steel section Entry. The capping experience is much more premium, and the whole pen feels premium too. The weight is exactly the same as the old one (both 24g on my scales inked and unposted) but the balance is more traditional as both body and section is Ti rather than a heavy steel section with light alu body. Also raw Ti has a slightly tacky feel so the section is grippier than the black coated steel which is helpful. I enjoy the high quality minimalist look of it a lot. The gravitas extra fine nib is also, unexpectedly, a joy. It is a little broader and wetter than I was expecting but has a touch of very pleasant feedback. I’m glad I got the EF as I think the F may have been a bit too much for my diary with normal paper.

For those looking to use this as a platform for swapping in Jowo nib units be aware that whilst the threads are the same the section is precision machined to fit the body of the gravitas/kanwrite nib unit which is a hair slimmer than most Jowos. Therefore some Jowo nib units will just about squeeze in and work fine, while others will not fit at all. So far two out of the three i’ve tried have fit with a little encouragement initially, but a third has not. I expect I can get that nib working in it by swapping it into a nib unit which does fit. So not the end of the world and I can use my other nibs but not a perfect fit for all Jowo nib units. I’m glad that the Gravitas nib is nice. Also note that I think the converter nipple is a hair thicker on the gravitas nib unit as the included converter is tight on that nib but loose on my Jowo nibs, so best to swap to a standard converter when swapping nibs, and vice versa if you put a gravitas nib in another pen, use the gravitas converter too, as my normal jowo nib converter is too tight.

Emy kindly fitted my initials to my new HomoSapiens Bronze Age. Matched the trim colour perfectly. Looks great. Emy’s personal attention to my emails and request etc were fabulous. I can highly recommend Pen Venture.

I picked the Bramble color because it is showy. The nib is wonderfully smooth and its size 6 better fits with my smaller hands (I'm 5'4") than the #8 on the full-size Titan. I could not tell any difference berween the slimline and regular Titan when filling and both nibs seemed equally smooth and wet. I really appreciate the clip (Boo! Gravitas). It is a terrific pen that I strongly recommend. I hope that Roy will next make Ultem barrels, which I think would eliminate the low possibility of staining the acrylic. I recommend this pen very highly.

I watched the video presentation three times before finally deciding to purchase this pen — and I couldn’t be happier that I did. This is my first Leonardo, and I am absolutely delighted. The craftsmanship is superb, the resin is truly mesmerizing, and the EF 14k gold nib is smooth, precise, and perfectly tuned. As a devoted Sailor user, I am especially impressed by the true extra-fine line this nib delivers, which is remarkable for a European nib.
A special mention goes to the beautiful handwritten note that accompanied the pen — such a thoughtful and personal touch, turning an already wonderful purchase into a truly memorable experience and I will definitely keep the note :) . Exceptional service. Thank you!

The Gravitas Piston carbon black fountain pen has it all:

- The pultruded carbon looks gorgeous and gives the pen a substantial feel in your hand even though it's relatively light. This is not a cheap pen and it does not feel like a cheap pen. You're going to love writing with this one!

- I previously assumed that I might not like the big #8 nib but once you've started using this pen you're going to love the #8

- I have this pen equipped with an extra-fine nib, and combined with the black ebonite feed it is a generous writer that lays a nice and precise line on the paper

- That grip section: made from Titanium and with extremely fine micro grooves it does not even feel like metal and it doesn't feel slippery in the least! (I own three more Gravitas pens with metal sections, two Sentries and a Pocket Carbon: The section on the "Piston" is outstanding and my favorite.)

- And finally: the piston mechanism is extremely smooth and easy-going!

... Go and buy a Gravitas Piston as long as they're available!

Fantástica tienda Con productos de gran calidad . Perfecto envío.

It is a beautiful pen, as pretty in the hand as it is in the photographs. Well made and it writes beautifully, as well, with a hint of feedback, less than a Sailor KOP but enough. Perfectly wet. It is a pleasure to have in my daily rotation.

Once again, dealing with Pen Venture and Emy was a great experience. Excellent and quick service. I'll be back!

This is a pen that fulfilled all its promises as soon as the nib it the page. I love the dark wine colour immensely. The girth was surprising, but welcome. I won't speak for other models, but this aluminium one is very comfortable and balanced in my average size male hand. My only criticism, not worth knocking off a star considering the rest, is that sometimes removing the cap loosens the section even though it is fitted with an o-ring. This has never caused a leak.
This is quality well worth the price.

After seeing this Quark Torlon's weight listed at a mere 8 grams, I couldn't help but be curious. It's shockingly light weight, but every bit as well made as the Quark Zirconium I have. Mine has a fine nib and it's wet enough to avoid feeling scratchy, even on cheap copy paper.
It's such a great contrast to heavier pocket pens while still being finely tuned and precision machined.

I picked up the Quark Zirconium with a fine nib to act as a counterpart to a Pocket Zirconium and ended up enjoying this tiny pen quite a lot more than I had expected to. While I typically gravitate towards medium nibs, I felt like the Quark was a perfect time to opt for a fine, and it made quite the impression.
I admittedly still prefer medium nibs for day to day use, I appreciate having the option to write just a bit finer And with the Quark, that option is always just a couple of seconds away. The threads for capping and posting are easy to start and feel very secure.
Then there's that splendid ringing you can get out of this little pen. It's something so simple but it always brings a smile to my face.

I picked this one up with a medium nib to pair alongside a Quark Zirconium with a fine nib, and I'm very glad I did. There's a cool smooth nature to the finish on the Pocket Zirconium which I am a big fan of. I'm also very pleased with the weight of the pen, as it gives it a distinct hand feel while writing. The nib is splendid, as I'm coming to expect from Gravitas.

Between the cap threads and oring it also seems to seal quite well, which is always important in any fountain pen. The all blacked out look is also very sleek. All in all, a splendid pocket pen that you won't forget is in your pocket.

Gravitas - Sentry Alu-Bronze