Inktend / Pen library / Pro Gear Slim
Sailor
Pro Gear Slim
Sailor's slimmer Pro Gear line, known for fine, precise gold nibs — the MF (medium-fine) size is a cult favorite for small handwriting.
A natural second or third pen for someone who's confirmed they enjoy the hobby and wants a nicer nib — not usually the first pen someone buys, but a common upgrade target.
Specs
About Sailor
Founded in Hiroshima in 1911, Sailor is Japan's oldest fountain pen maker, known for precisely ground gold nibs and its own line of bottled inks. This model — Pro Gear Slim — dates to a slimmer variant of Sailor's long-running Pro Gear line.
How to fill the Sailor Pro Gear Slim
Fill it two ways: snap in a pre-filled international cartridge for convenience, or use a converter — a small plunger or twist mechanism that installs the same way a cartridge does — to draw ink from any bottle. The converter route opens up the entire world of bottled ink, which is where most of the hobby's color variety lives.
Choosing a nib size
Nib size determines line width, not writing pressure — fountain pens are meant to glide, never press. Extra-fine (EF) suits small, dense handwriting and thin paper; fine (F) is the most broadly recommended default; medium (M) shows more ink character and shading; broad (B) and stub grinds favor bold, expressive strokes and calligraphy-adjacent writing. The Pro Gear Slim's gold nib will also flex slightly with pressure, giving line variation that a steel nib of the same size won't produce.
Keeping it clean
A quick flush with cool water every time you switch ink colors — and a full clean every 4–6 weeks of regular use — is enough to keep the nib and feed performing well. Inktend's cleaning reminder is tuned to a 21-day baseline and adjusts naturally to how often you actually refill.
Pairing inks with the Pro Gear Slim
Because refills are quick with a cartridge or converter, this is a good pen for rotating through several colors rather than committing to one; sample vials work especially well here.
Frequently asked questions
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Specs on this page have been individually verified against manufacturer and retailer listings.