Radius Prisma Fountain Pen: A Limited Edition With Rainbow PVD Trim

Introduction

Some limited editions feel like rebrands with a new finish. The Radius Prisma, produced with the Italian retailer Stilo&Stile, manages to feel a little different. Radius is a brand with genuine history: it was founded in 1934 in Turin, in northern Italy, and produced pens for roughly twenty years until the mid-1950s. Today the brand is owned by Leonardo, which began producing pens under the Radius name in 2019 based on historical designs.

The Prisma itself is based on a model called the Antartctica, and this version is a limited edition of 300 units. It wears a frosted white Italian resin that Stilo&Stile has used on several of its previous collaborations, and it is accented with a rainbow PVD trim treatment. If you have enjoyed the retailer’s earlier Leonardo collaborations, this one slots neatly into that same lineage.

Design and Materials

The cap ends in a rounded conical tip that transitions into the clip. The clip sits on the shorter side, and the rainbow gradient application means just about every pen will look slightly different. Functionally it is not too stiff and slips comfortably into a pocket or shirt. The cap angles upward at an even rate of incline, and the frosted matte material is translucent enough to give you a faint peek at the shadow of the nib inside.

The cap band is one of the most distinctive details: three connected bands with a diamond pattern of cutouts, through which you can see the underlying resin. The back of the cap carries the Radius and Stilo&Stile engraving along with the limited edition number. The barrel is slightly rounded with a gentle taper to a rounded cone tip at the end, mirroring the cap. The matte texture feels genuinely nice in the hand, providing an easy, secure grip.

Build and Filling

The cap twists off with a single rotation, revealing a number six stainless steel JoWo nib with the same rainbow PVD treatment, available in extra fine, fine, medium, broad, and a 1.1 stub. The section is a bit on the short side, beginning with a slight flare before rising to the threads and a thin rainbow band. Because of the smaller section, my grip comes into contact with the threads, but they are smooth enough that it is barely noticeable.

The Prisma is long enough to use unposted, and the cap posts deeply and securely without unbalancing the pen, so both posting styles work well. This is a cartridge/converter pen accepting standard international cartridges, and a converter is included. Although the barrel is one piece, eyedropping would not be recommended. Two details worth appreciating: the PVD treatment extends onto the section threads, and it is even included on the extended metal piston knob of the converter. When the pen is in use, you get a decent look at the rainbow through the frosted Italian resin.

Nib and Writing Performance

The stainless steel JoWo nib is not perfectly smooth; it carries a touch of feedback, though the kind that reassures you that you are writing with a fountain pen. Do not expect significant line variation here.

Ink flow is on the decent side, and the feed keeps up just fine with fast writing. Reverse writing is not too scratchy but a little inconsistent in ink flow. With a medium nib the overall writing experience is pleasant and understated, much like the rainbow treatment itself: it has some color but not too much flash, which is exactly the appeal.

Size Comparisons

Next to the Leonardo Momento Zero, the Prisma is slightly shorter but slightly thicker. It sits comfortably alongside the retailer’s other limited editions, including the Pura, the Como, and the Micarta, all of which share that same sense of restrained Italian styling. It also compares well against the Delta DV, the Montegrappa Elmo Chiuso Cola, and the Sailor Pro Gear. The Prisma fits into this company without looking like just another Momento Zero, which is arguably its greatest design achievement: similar in spirit, but clearly its own pen.

Pricing and Availability

The Prisma is available only through Stilo&Stile and launched on November 2nd at 6:00 p.m. Italy time, which is noon Eastern. It retails for €195 for customers within the EU, while customers outside the EU who do not pay VAT pay around €159, which equates to roughly $169. A promotional code (FPD2023) offered an additional 10% discount during a two-day window after launch.

The standard Radius models that this pen is based on typically sell in the low €200 range, so the non-VAT price of around $169 is very reasonable for what you receive. With only 300 units in existence, these were expected to sell out quickly.

Buying Advice

If the frosted resin and subtle rainbow trim appeal to you, act on any remaining stock sooner rather than later, because limited runs like this rarely linger. The reasonable pricing relative to standard Radius models makes the value proposition straightforward.

This pen suits collectors who already appreciate Italian limited editions and anyone who wants a cartridge/converter daily writer that posts and unposts comfortably. Skip it if you need a larger section, prefer perfectly smooth nibs, or want a pen you can eyedropper.

Conclusion

The Radius Prisma is an interesting first close look at a revived brand, and it will be worth watching what Leonardo does with Radius next. It is different enough from the Momento Zero line to stand on its own, the frosted Italian resin and rainbow PVD treatment are genuinely well executed, and the limited edition of 300 units gives it a collectible edge. For fans of Italian pens, it is an easy recommendation at this price.