TWSBI GO: Spring Piston, 1.61 ml & Nib Sizes
The TWSBI GO is TWSBI's lowest-priced fountain pen, a clear resin pen with a spring-loaded piston: press the plunger down, release it, and the barrel fills from a bottle. Goulet Pens lists it at 134 mm (5.3 in) capped, 17.0 g and up to 1.61 ml of ink. It has a steel nib and a clipless snap cap.
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Product facts
- Product
- TWSBI GO Fountain Pen (Clear)
- Brand
- TWSBI
- Brand origin
- Taiwan
- Made in
- Taiwan*
- Material
- Clear resin body, cap and grip; stainless steel nib
- Price range
- $$$$20–75 per pen (multi-packs divided by the count)
Notes on these facts
- Made by TaShin Precision (Taiwan). Made in Taiwan: Goldspot's TWSBI GO listing says "Made in Taiwan". TWSBI's own store says the brand was started by TaShin Precision after 50-plus years as an OEM manufacturer, but its GO page doesn't print a country of manufacture. TWSBI's Taiwanese site, twsbi.com.tw, refused our connection on October 21, 2026. Source. Price: example listing.
- Price bands are typical US retail, checked October 2026.
Key takeaways
- Goulet Pens lists a maximum capacity of 1.61 ml, about four times the 0.4 ml of a Pilot CON-40 converter.
- It is 134 mm (5.3 in) capped, 125 mm (4.9 in) with the cap off and 171.9 mm (6.8 in) posted, with a 14.7 mm body, per Goulet.
- Goulet weighs it at 17.0 g: 12 g for the body and 5 g for the clipless snap cap.
- TWSBI sells it with steel nibs in EF, F, M, B and 1.1 mm stub, and listed the Clear GO at US$21.99 on October 21, 2026.
- Goldspot lists it as made in Taiwan; TWSBI is the own brand of Taiwanese OEM maker TaShin Precision.
What is the TWSBI GO?
The GO is TWSBI’s lowest-priced fountain pen: a clear, chunky resin pen that fills itself with a spring-loaded plunger instead of a twist piston. Goulet Pens calls it the most affordable TWSBI yet. TWSBI is the own brand of Taiwan’s TaShin Precision, which also makes the TWSBI ECO and Diamond 580.
It’s also one of the most reviewed fountain pens at Goulet: 144 customer reviews on the Clear GO listing in October 2026, more than the Pilot Falcon’s 116 or the LAMY CP1’s 106 on the same site.
How does the spring-loaded piston work?
You dip the nib in ink, press the plunger at the back down to compress the spring, and let go: the spring pulls the seal back and the barrel fills. TWSBI’s own listing puts it as “simply press down and release and you’re ready to GO”.
Goulet describes it with the barrel unscrewed to reach the plunger, then screwed back on to write. Goldspot says it sucks up ink in one simple stroke, where the ECO and 580 need several turns of a piston knob.
TWSBI GO specs
| Spec | Value |
|---|---|
| Maker | TaShin Precision (TWSBI), Taiwan |
| Body and cap | Clear resin; clipless snap cap |
| Filling | Spring-loaded piston, bottled ink only |
| Ink capacity | 1.61 ml max (Goulet) |
| Nib | Stainless steel: EF, F, M, B, 1.1 mm stub (TWSBI) |
| Length capped | 134 mm (5.3 in) |
| Length cap off | 125 mm (4.9 in), with a 17.6 mm visible nib |
| Length posted | 171.9 mm (6.8 in); Goldspot: 172 mm |
| Cap | 60.4 mm (2.4 in) |
| Diameter | 14.7 mm body (Goldspot: 14.5 mm), 17.2 mm cap, 10.0 mm grip |
| Weight | 17.0 g (12 g body, 5 g cap) |
| Made in | Taiwan (Goldspot) |
Lengths, diameters and weights are Goulet Pens’ figures; Goldspot’s match apart from a 14.5 mm barrel. TWSBI’s item codes run from M7447310 (EF) to M7447350 (1.1 mm stub) for the Clear GO.
How much ink does the GO hold?
Up to 1.61 ml, by Goulet Pens’ measurement. That’s about four times the 0.4 ml Unsharpen lists for a Pilot CON-40 converter, and close to the twist-piston TWSBIs.
A clear barrel makes it easy to see when you’re running low, and a big tank suits a bottled ink such as Noodler’s Black.
How does the GO compare to the TWSBI ECO and Diamond 580?
The GO is the simplest and cheapest; the ECO and 580 use twist pistons, hold a little more and have clips.
| TWSBI GO | TWSBI ECO | TWSBI Diamond 580 | |
|---|---|---|---|
| Filling | Spring piston | Twist piston | Twist piston |
| Capacity | 1.61 ml | 1.76 ml | 1.98 ml |
| Capped | 134 mm | 138.8 mm | 142 mm |
| Weight | 17.0 g | 21 g | 28.0 g |
| Clip | No | Yes | Yes |
| Price band | $$$ | $$$ | $$$ |
ECO and 580 figures come from their guides. At 14.7 mm, the GO’s body is also wider than the 580’s 13.3 mm.
Which nib should you choose?
F for most writing, which TWSBI’s store calls its most popular size; EF if you write small. TWSBI suggests M for bigger handwriting, B for headers and signatures, and the 1.1 mm stub for italic-style lettering on cards.
Where is the TWSBI GO made?
In Taiwan, according to Goldspot. TWSBI’s store says the brand belongs to Taiwanese OEM maker TaShin Precision but doesn’t print a country of manufacture, and its Taiwanese site refused our connection on October 21, 2026.
How much does a TWSBI GO cost?
The GO sits at the bottom of our $$$ price band, $20–75 per pen: TWSBI and Goulet Pens both listed the Clear GO at US$21.99 on October 21, 2026. TWSBI notes that ink isn’t included, so add a bottle.
Frequently asked questions
How do you fill a TWSBI GO?
Dip the nib in bottled ink, press the plunger at the end of the pen down against its spring and let it go; the spring pulls the seal back and draws ink into the barrel. TWSBI calls it press down and release.
How much ink does the TWSBI GO hold?
Goulet Pens lists a maximum of 1.61 ml. That is a little less than the TWSBI ECO's 1.76 ml but far more than a typical cartridge converter.
Does the TWSBI GO take cartridges?
No. It fills from bottled ink only, through its built-in spring piston.
Does the TWSBI GO have a clip?
No. The snap-on cap is clipless, so the GO won't clip into a pocket; Goldspot says it gives an unobstructed view into the pen.
What nib sizes does the TWSBI GO come in?
Extra Fine, Fine, Medium, Broad and a 1.1 mm stub, all stainless steel. TWSBI's store says F is its most popular size.
Is the TWSBI GO good for beginners?
It is TWSBI's lowest-priced pen and very simple to fill, which makes it a common first piston filler. It needs a bottle of ink, so budget for one.
Where is the TWSBI GO made?
In Taiwan, according to Goldspot. TWSBI is the brand of Taiwanese maker TaShin Precision.
Sources
- TWSBI: GO Clear Fountain Pen (official store; spring-loaded piston, EF to Stub 1.1, item codes, US$21.99, ink not included)
- TWSBI: About us (TaShin Precision, 50-plus years as an OEM manufacturer)
- Goulet Pens: TWSBI GO, Clear (dimensions, 17.0 g, 1.61 ml, how to fill, snap cap)
- Goldspot: TWSBI GO, Smoke (specifications, 14.5 mm barrel, made in Taiwan)
- Unsharpen: Pilot CON-40 converter (0.4 ml)