--- title: "TWSBI Diamond 580: Piston Capacity, Nibs & 580AL" canonical: "https://stationerytimes.com/guides/twsbi-diamond-580/" description: "TWSBI Diamond 580 fountain pen explained: a clear piston filler holding up to 1.98 ml, 142 mm capped and 28 g, swappable steel nibs, and the 580AL and 580ALR." category: "Pens" type: "Fountain pen" published: 2026-10-20 updated: 2026-10-20 author: "Ellis Penhale" publisher: "Stationery Times" sources: 16 products: - name: "TWSBI Diamond 580 Fountain Pen (Clear)" brand: "TWSBI" brand_origin: "Taiwan" made_in: "Taiwan" material: "Resin body, cap and grip; steel nib" price_band: "$$$ ($20–75 per pen (multi-packs divided by the count), typical US retail, October 2026)" manufacturer: "TaShin Precision (Taiwan)" model: "Diamond 580" sku: "M7443120" url: "https://www.twsbi.com/products/twsbi-diamond-580-clear-fountain-pen" --- # TWSBI Diamond 580: Piston Capacity, Nibs & 580AL > The TWSBI Diamond 580 is a clear, faceted piston-filling fountain pen from Taiwan's TWSBI. Goulet Pens lists it at 142 mm (5.6 in) capped and 28.0 g, with a maximum ink capacity of 1.98 ml from bottled ink. Its steel nib unit unscrews for swapping, and the 580AL and 580ALR add aluminium parts. - URL: https://stationerytimes.com/guides/twsbi-diamond-580/ - Category: Pens - Author: Ellis Penhale - Published: 2026-10-20 - Updated: 2026-10-20 ![Side view of a clear TWSBI Diamond 580 fountain pen with the cap off, drawn to scale: 130 mm (5.1 in) long, with blue ink in the faceted barrel, the piston rod and seal behind it, and an inset of the piston seal, up to 1.98 ml](https://stationerytimes.com/images/raster/twsbi-diamond-580-16x9.png) *The Diamond 580 in Clear, cap off, to scale at Goulet Pens' 130 mm.* Original drawing (SVG): https://stationerytimes.com/images/twsbi-diamond-580-cover.svg. Drawings © 2026 Stationery Times, reusable with credit under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ## Product facts | Product | Brand | Brand origin | Made in | Material | Released | Price range (typical US retail, October 2026) | |---|---|---|---|---|---|---| | TWSBI Diamond 580 Fountain Pen (Clear) | TWSBI (by TaShin Precision (Taiwan)) | Taiwan | Taiwan | Resin body, cap and grip; steel nib | – | $$$: $20–75 per pen (multi-packs divided by the count) | - Made in (TWSBI Diamond 580 Fountain Pen (Clear)): Taiwan. LarryPOST lists "Origin: Taiwan". TWSBI's own site says the brand was started by TaShin Precision, a Taiwanese maker with 50-plus years as an OEM manufacturer, but its product pages don't print a country of manufacture. JetPens says TWSBI's nibs themselves are made in Germany. TWSBI's Taiwanese site, twsbi.com.tw, didn't load for us on October 20, 2026. Source: https://www.larrypost.com.au/products/twsbi-diamond-580rbt-fountain-pen-red-blue-transparent ## Key takeaways - TWSBI says the 580 holds about 30% more ink than the 530; Goulet Pens lists a maximum of 1.98 ml, LarryPOST up to 1.9 ml and JetPens 1.5 ml with a basic fill. - It is 142 mm (5.6 in) capped and 130 mm (5.1 in) with the cap off, with a 13.3 mm body and a 10.0 mm grip, per Goulet. - Goulet weighs it at 28.0 g (14 g body, 14 g cap); it lists the aluminium 580AL at 31.0 g and the 580ALR at 27.0 g. - TWSBI sells steel nib units in EF, F, M, B and 1.1 mm stub that also fit the older Diamond 540 and 530; its own store lists the Clear 580 at US$55.99. - LarryPOST lists Taiwan as the origin; TWSBI is the own brand of Taiwan's TaShin Precision, and JetPens says the nibs are made in Germany. ## What is the TWSBI Diamond 580? **The Diamond 580 is TWSBI's faceted, clear piston-filling fountain pen: the barrel itself is the ink tank, filled by twisting the knob at the end.** TWSBI's own site says the brand was started by TaShin Precision, a Taiwanese company with more than 50 years as an OEM manufacturer of plastic and metal parts, which also makes the [TWSBI ECO](https://stationerytimes.com/guides/twsbi-eco/). TWSBI says the 580 followed the Diamond 530 and 540, with an improved grip and end barrel, smoother cap threads and about 30% more ink than the 530. It's one of the pens enthusiasts name most for a second fountain pen: a Fountain Pen Network thread on the best mid-priced pens lists the TWSBI 580 next to the [LAMY 2000](https://stationerytimes.com/guides/lamy-2000/) and Pelikan M200. ## TWSBI Diamond 580 specs | Spec | Value | |---|---| | Maker | TaShin Precision (TWSBI), Taiwan | | Body and cap | Clear faceted plastic, screw-on cap | | Filling | Built-in piston, bottled ink only | | Ink capacity | About 30% more than the 530 (TWSBI); 1.98 ml max (Goulet); about 2 ml (Goldspot); 1.5 ml basic fill (JetPens, 580ALR) | | Nib | Steel, size 6 (Unsharpen): EF, F, M, B, 1.1 mm stub (TWSBI) | | Length capped | 142 mm (5.6 in) | | Length cap off | 130 mm (5.1 in), with a 19 mm visible nib | | Cap | 60 mm (2.4 in) long | | Diameter | 13.3 mm body, 14.4 mm cap (18.6 mm with clip), 10.0 mm grip | | Weight | 28.0 g (14 g body, 14 g cap) | | In the box | Wrench and silicone grease | | Made in | Taiwan (LarryPOST) | All lengths, diameters and weights are from Goulet Pens' listing. JetPens lists the 580ALR at 143 mm capped and 130 mm uncapped. TWSBI's store listed the Clear 580 at US$55.99 on October 20, 2026, with item codes M7443110 (EF) to M7443150 (1.1 mm stub). ![TWSBI Diamond 580 to scale: 142 mm capped, 130 mm body with the cap off, 60 mm cap; 28.0 g, piston up to 1.98 ml](https://stationerytimes.com/images/twsbi-diamond-580-lengths.svg) *The cap is 60 mm long and doesn't post securely, so most people write with it off.* ## How much ink does the Diamond 580 hold? **Up to 1.98 ml by Goulet Pens' measurement, about five times the 0.4 ml of a Pilot CON-40 converter.** TWSBI itself only says it holds about 30% more than the 530. Retailers round it differently: LarryPOST says up to 1.9 ml, Goldspot about 2 ml, and JetPens lists 1.5 ml with a basic fill and up to about 1.95 ml with extra steps. That's a little more than the 1.76 ml Goulet measures for the TWSBI ECO. A big tank suits long writing sessions and inks you want to see sloshing through the clear barrel; a bottle like [Noodler's Black](https://stationerytimes.com/guides/noodlers-black-ink/) fills it many times over. ## Can you post the cap? **Not securely.** Goulet's listing marks it as not postable, and JetPens says posting is possible but makes the pen very long and top-heavy, and that twisting a posted cap can turn the piston knob. ## What's the difference between the 580, 580AL and 580ALR? **The 580 is all plastic; TWSBI says the AL has an aluminium grip, connector and piston rod, and the ALR adds a matte finish with subtle details on the grip and cap.** | Model | What changes | Weight | |---|---|---| | Diamond 580 | Plastic grip and internal parts | 28.0 g (Goulet) | | Diamond 580AL | Aluminium grip, connector and piston rod (TWSBI) | 31.0 g (Goulet listing) | | Diamond 580ALR | AL parts with a matte finish and circular engravings on the grip and cap | 27.0 g (Goulet); 27 g (JetPens) | Goulet's blog counts four aluminium parts, says they add durability, and puts the 580AL at 32 g, 1 g more than its own listing. Most current releases are ALR-based, per LarryPOST. On October 20, 2026 TWSBI listed the 580AL and 580ALR at US$72.99. ## Can you swap the nib? **Yes: the nib and feed unscrew from the grip as one unit.** TWSBI sells Diamond 580 nib sets in EF, F, M, B and 1.1 mm stub at US$22.99 each, and says they also fit the older Diamond 540 and 530. TWSBI nibs use Western sizing, per JetPens, so a 580 Fine writes broader than a Japanese Fine like the [Pilot Custom 74](https://stationerytimes.com/guides/pilot-custom-74/)'s. ## How does the 580 compare to the TWSBI ECO? **The 580 is a little heavier and holds a bit more, and its nib unit swaps without tools; the ECO is lighter and costs less.** | | TWSBI Diamond 580 | [TWSBI ECO](https://stationerytimes.com/guides/twsbi-eco/) | |---|---|---| | Capacity | 1.98 ml | 1.76 ml | | Capped | 142 mm | 138.8 mm | | Weight | 28.0 g | 21 g | | Nib swap | Screw-out nib unit | Uses a TWSBI Mini unit | | Posts | Not securely | Yes, 167.5 mm | | Price band | $$$ | $$$ | ECO figures come from its guide. ## Where is the TWSBI Diamond 580 made? **In Taiwan, according to LarryPOST.** TWSBI's site says the brand belongs to Taiwanese maker TaShin Precision but doesn't print a country of manufacture on the product page, and its Taiwanese site didn't load for us. JetPens says TWSBI's nibs themselves are made in Germany. ## How much does a TWSBI Diamond 580 cost? **The plain 580 is in our $$$ price band, $20–75 per pen: on October 20, 2026, TWSBI listed it at US$55.99, and the 580AL and 580ALR at US$72.99.** Check current prices when you buy, and budget for a bottle of ink, since it can't take cartridges. ## Frequently asked questions ### How much ink does the TWSBI Diamond 580 hold? Goulet Pens lists a maximum of 1.98 ml and Goldspot says about 2 ml. JetPens lists 1.5 ml with a basic fill and up to about 1.95 ml with extra steps, so expect roughly 1.5 to 2 ml. ### Can you post the cap on a TWSBI 580? Not well. Goulet says the cap doesn't post securely, and JetPens says posting makes the pen long and top-heavy, and twisting a posted cap can turn the piston. ### What is the difference between the TWSBI 580, 580AL and 580ALR? The 580 is all plastic. TWSBI says the 580AL has an aluminium grip, connector and piston rod, and the 580ALR adds a matte finish with subtle details on the grip and cap. ### Does the TWSBI Diamond 580 take cartridges? No. It is a piston filler designed for bottled ink only, so there is no cartridge or converter. ### What nib sizes does the TWSBI 580 come in? Extra Fine, Fine, Medium, Bold and a 1.1 mm stub, per TWSBI's store. TWSBI says its replacement nib sets also fit the older Diamond 540 and 530. ### What comes in the TWSBI 580 box? Goulet says the pen comes with a wrench and silicone grease for long-term maintenance of the piston, not for use on day one. ### Where is the TWSBI Diamond 580 made? In Taiwan, according to LarryPOST; TWSBI is the brand of Taiwanese maker TaShin Precision. JetPens says TWSBI's nibs are made in Germany. ## Sources - [TWSBI: Diamond 580 Clear Fountain Pen (official store; about 30% more ink than the 530, nib sizes, item codes, US$55.99)](https://www.twsbi.com/products/twsbi-diamond-580-clear-fountain-pen) - [TWSBI: Diamond 580 Nib Set (EF to Stub 1.1; fits the 540 and 530)](https://www.twsbi.com/products/twsbi-diamond-580-nib-set) - [TWSBI: Diamond 580AL Silver (aluminium grip, connector and piston rod)](https://www.twsbi.com/products/twsbi-diamond-580al-fountain-pen) - [TWSBI: Diamond 580ALR Prussian Blue (matte finish, details on grip and cap)](https://www.twsbi.com/products/twsbi-diamond-580alr-prussian-blue-fountain-pen) - [TWSBI: About us (TaShin Precision, 50-plus years as an OEM manufacturer)](https://www.twsbi.com/pages/about-us) - [Goulet Pens: TWSBI Diamond 580, Clear (dimensions, 28.0 g, 1.98 ml, wrench and grease)](https://www.gouletpens.com/products/twsbi-diamond-580-fountain-pen-clear) - [Goulet Pens: TWSBI Diamond 580AL, Silver (31.0 g)](https://www.gouletpens.com/products/twsbi-diamond-580al-fountain-pen-silver) - [Goulet Pens: TWSBI Diamond 580ALR, Nickel Gray (27.0 g)](https://www.gouletpens.com/products/twsbi-diamond-580alr-fountain-pen-nickel-gray) - [Goulet Pens: TWSBI 580, 580AL and 580ALR, what's the difference?](https://www.gouletpens.com/blogs/fountain-pen-blog/twsbi-580al-vs-twsbi-580) - [JetPens: TWSBI Diamond 580ALR Prussian Blue (27 g, 1.5 ml, posting, German-made nibs)](https://www.jetpens.com/go/miyia382) - [LarryPOST: TWSBI Diamond 580RBT (origin Taiwan, up to 1.9 ml)](https://www.larrypost.com.au/products/twsbi-diamond-580rbt-fountain-pen-red-blue-transparent) - [Goldspot: TWSBI Diamond 580, Iris (about 2 ml)](https://goldspot.com/products/twsbi-diamond-580-fountain-pen-in-iris) - [The Gentleman Stationer: TWSBI Diamond 580 Clear (530 and 540 lineage)](https://www.gentlemanstationer.com/the-curated-shop/twsbi-580-clear-fountain-pen) - [Unsharpen: TWSBI Diamond 580 review (nib sizes)](https://unsharpen.com/pen/twsbi-diamond-580/) - [Unsharpen: Pilot CON-40 converter (0.4 ml)](https://unsharpen.com/refill/pilot-con-40-fountain-pen-converter/) - [Fountain Pen Network: Best pens under $200 (forum thread)](https://fountainpennetwork.com/forum/topic/288755-best-pens-under-200)