Compiled from 6 sources; we haven't tested this product ourselves yet. How we research
Quick answer
The Opus 88 Koloro is a mid-size Taiwanese eyedropper fountain pen that combines colored ebonite with clear acrylic. You fill the barrel from a dropper, and a rear valve shuts the ink off when you're done. Vanness lists 142.2 mm capped; eslite lists 23.5 g. Goldspot says it's made in Taiwan. It sits in our $$$$ band.
On this page9 sections
The Blue Koloro, 142.2 mm capped; unscrew the rear to write.
Product facts
Product
Opus 88 Koloro eyedropper fountain pen, Blue, Fine nib
$$$$over $75 per pen (multi-packs divided by the count)
Colors
Blue Blue
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Notes on these facts
Made by Opus 88 (精基文具), Taiwan. Made in Taiwan: Goldspot's Koloro listing (read October 23, 2026) says "Made in Taiwan". eslite's Taiwanese listing titles it 台灣OPUS 88製筆 (pens made by Taiwan's OPUS 88) and says the nib is imported from Germany. Source. Price: example listing.
Colors: names per Pen Chalet, checked October 24, 2026. Colors as Pen Chalet names them; none is marked as a limited edition. Goldspot sells further Koloro editions, such as Light Blue 2025 Edition and Beige Ebonite, which aren't listed here. Tints were sampled from Pen Chalet's product photos. The upper half of each tile is the acrylic barrel and the lower half the cap top and end. Tints are representative, not measured. Shops stock different colors.
Price bands are typical US retail, checked October 2026. Conversions to US dollars are approximate, at October 2026 rates (US$1 = ¥158 = ₩1,330 = NT$32.5 = CN¥6.7 = SEK 9.9 = DKK 6.7 = ₺49.6 = C$1.41 = A$1.43 = CZK 21.7; €1 = US$1.12; £1 = US$1.32; CHF 1 = US$1.21).
Key takeaways
Vanness lists the Koloro at 142.2 mm (5.6 in) capped and 158.8 mm (6.25 in) posted, with a 10.9 mm grip.
eslite's Taiwanese listing gives 23.5 g, a 1.5 × 1.5 × 14.1 cm item size and acrylic, copper and ebonite materials.
eslite lists the Blue Koloro with an F nib at NT$2,800 (about US$86) in Taiwan.
eslite claims nearly 5 cc of ink, enough for close to half a year of writing; we haven't measured it.
Goldspot's listing says the Koloro is made in Taiwan; Vanness says the nib is a JoWo #5 in stainless steel.
What is the Opus 88 Koloro?
It’s a mid-size eyedropper fountain pen from Taiwan’s Opus 88, made by joining colored ebonite to clear acrylic. The whole barrel holds ink, and a valve at the back opens and closes the flow to the nib.
eslite’s Taiwanese listing says this traditional Japanese-style eyedropper system was once used only on very expensive urushi and maki-e pens, and that Opus 88 builds it from affordable ebonite and acrylic instead. It calls joining the two materials technically difficult.
Opus 88, trading in Taiwan as 精基文具, began as an OEM maker for European and American brands and launched its own name in early 2017, eslite says. The Koloro is stocked by US retailers including Goldspot and Vanness.
Opus 88 Koloro specs
Spec
Opus 88 Koloro
Length capped
142.2 mm (5.6 in) (Vanness)
Length posted
158.8 mm (6.25 in) (Vanness)
Grip
10.9 mm (Vanness)
Item size
1.5 × 1.5 × 14.1 cm (eslite)
Weight
23.5 g (eslite)
Materials
Acrylic, copper alloy (銅), ebonite (eslite)
Nib
JoWo #5 stainless steel (Vanness)
Ink capacity
Nearly 5 cc, claimed (eslite)
Taiwan price
NT$2,800 (about US$86), Blue F (eslite)
Goldspot’s item number for the Blue Fine is 96083902F, the same EAN as eslite’s listing, 4710484640710. Vanness lists a body diameter it garbles, so we use eslite’s 1.5 cm item size as a rough width.
How do you fill the Opus 88 Koloro?
Unscrew the section from the barrel, drop bottled ink into the barrel with the eyedropper in the box, and screw the section back. Vanness and eslite describe the same steps.
Leave a little air below the threads. A Goulet ink syringe does the same job with less mess, and our guide to filling a fountain pen covers eyedroppers alongside other systems.
How does the shut-off valve work?
A rod runs from the blind cap at the back to a seal behind the feed; screw it closed and ink can’t reach the nib. eslite’s instructions say to loosen the rear knob slightly when writing and tighten it when you’re done, to avoid leaks and seepage.
Vanness says unscrewing the blind cap releases the middle piston rod’s shut-off mechanism. If the pen writes dry after a while, the valve is the first thing to check.
How does the Koloro compare to the Opus 88 Jazz?
The Koloro is shorter and lighter, while both fill the same way and have a rear valve. The Opus 88 Jazz is the larger, torpedo-shaped model.
Opus 88 Koloro
Opus 88 Jazz
Length capped
142.2 mm (5.6 in)
151.2 mm (6.0 in)
Weight
23.5 g (eslite)
28.0 g (Goulet)
Materials
Ebonite and acrylic
Acrylic and resin, ebonite valve rod
Claimed capacity
Nearly 5 cc (eslite)
Nearly 5 cc (eslite); Goulet measured 2.97 ml
Price band
$$$$
$$$$
The Koloro beside the larger Jazz, capped and drawn to one scale.
Goulet’s 2.97 ml measurement for the Jazz suggests eslite’s “nearly 5 cc” is generous; we haven’t measured the Koloro. If you’d rather start with a cheaper bottle-filling pen, the TWSBI ECO is a piston filler in our $$$ band.
Where is the Opus 88 Koloro made?
In Taiwan, according to Goldspot’s listing. eslite titles it “pens made by Taiwan’s OPUS 88” and says the nib is imported from Germany, matching Vanness’s JoWo #5.
Clean an eyedropper by emptying the barrel and flushing it with water; our cleaning guide has the steps.
Frequently asked questions
How do you fill an Opus 88 Koloro?
Unscrew the section from the barrel, fill the barrel with bottled ink using the included eyedropper, and screw the section back on, as Vanness and eslite describe.
Why won't my Opus 88 Koloro write?
The shut-off valve is probably closed. eslite's instructions say to loosen the knob at the back slightly while writing and screw it tight when you stop.
Does the Koloro take cartridges or a converter?
No. It's an eyedropper-only pen; Goldspot says it comes gift boxed with an eyedropper instead.
Can you use shimmer ink in the Opus 88 Koloro?
eslite's listing says its eyedroppers can be used with shimmering inks. Rinse the barrel promptly afterward so particles don't settle.
Is the Koloro smaller than the Opus 88 Jazz?
Yes. The Koloro is 142.2 mm capped per Vanness and 23.5 g per eslite; Goulet Pens measures the Jazz at 151.2 mm and 28.0 g.
What is ebonite?
Hardened rubber, a traditional pen material. eslite says Opus 88 joins colored ebonite to acrylic on the Koloro, which it calls technically difficult.
What colors does the Opus 88 Koloro come in?
Pen Chalet lists seven: Blue Blue, Blue Tan, Red Red, Orange Yellow, Amber/White, Pink/White and White Blue, each pairing a colored acrylic barrel with a cap top and end in a second color. Goldspot sells further editions, such as a 2025 Light Blue.
