Ensso XS Ultem Pocket Fountain Pen Review: Small, Light, and Surprisingly Fun

Introduction

The Ensso XS has been around before, and it earned a loyal following as a genuinely useful pocket fountain pen. This new version keeps the same model but swaps the body material for Ultem, a translucent amber-toned plastic with real credentials: it is very light, very strong, and heat resistant, which is why it shows up in aerospace applications. It is a small pen, and that is entirely the point, but posting the cap turns it into a comfortably usable daily writer.

Design and Materials

Ultem gives the XS a distinct warm yellow translucency that is hard to mistake for standard clear plastic. The barrel is faceted rather than round, which is subtle at a distance but obvious up close, and the facets do a practical job: the pen lies still on a desk instead of rolling away. The section is transparent too, so you can see the ink level in the cartridge, which some people will love and others will not.

The pen ships in a simple, fully recyclable box with a small ziplock bag containing a spare O-ring and the removable clip. The clip pops off with relative ease if you prefer an even more minimalist look. An O-ring holds the cap in place, and a second O-ring at the rear of the barrel lets the cap post securely. The whole body takes standard international short cartridges, and with the existing O-ring and some silicone grease, an eyedropper conversion may be possible, though that has not been tested.

Nibs and Writing Performance

Both versions use a Bock number 5 nib. The polished stainless steel version runs closer to a fine, while the black coated version sits nearer a medium. Neither nib carries a visible grade marking, so the sizing is based on how they write. The coating on the black nib initially produces noticeable feedback, but once the coating wears off the tipping, it smooths out considerably.

Writing Performance

Unposted, the XS is too small for many hands, but posted it becomes a pleasant, well-balanced writer. Both nibs are surprisingly wet, especially the fine, and both are round points with no natural line variation, though a careful hand can coax a little line variation out of them since the tipping is responsive. Reverse writing is scratchy and dry on both, so that is best avoided.

The black coated nib is the smoother of the two and feels slightly less springy, possibly due to the coating, while the stainless fine has a touch more feedback that is not unpleasant. Both were used extensively and wrote reliably throughout.

Things to Consider Before Buying

The O-ring cap and posting system is the main long-term consideration. O-rings wear over time because there is friction every time you cap or post the pen, and a spare is included with each pen. In practice, the older titanium XS is still going strong after years, and replacement O-rings cost pennies at any hardware store. A tiny amount of silicone grease on the O-ring can help extend its life. If you dislike visible ink through a translucent section, this material may not suit you.

Buying Advice

At $89, this is not a cheap pocket pen, but it is a limited run of 150 pieces in each finish, nicely made, and a very reliable writer in a more special material. It fits flush in a shirt breast pocket without the bulk of a full-size pen, which makes it genuinely practical for anyone who carries a pen daily. Keep an eye out for discount codes on the Ensso website, as they apply across the store and can soften the price meaningfully.

Conclusion

The Ensso XS Ultem takes a proven pocket pen formula and gives it a distinctive, functional material upgrade. It is small, light, cute, and writes better than its size suggests. The O-ring design requires a little maintenance awareness, but that is a fair trade for such a compact, clipped-optional everyday carry pen.