--- title: "Pilot CON-40 Converter: Capacity, Fit & Filling" canonical: "https://stationerytimes.com/guides/pilot-con-40-converter/" description: "Pilot CON-40 converter explained: a 60 mm twist converter holding 0.4 ml, four metal agitators, which Pilot pens it fits, why it looks half full, how to fill." category: "Accessories" type: "Fountain pen converter" published: 2026-10-22 updated: 2026-10-22 author: "Ellis Penhale" publisher: "Stationery Times" sources: 4 products: - name: "Pilot CON-40 converter" brand: "Pilot" brand_origin: "Japan" made_in: "Not stated" material: "Clear plastic barrel, plastic twist knob and piston, metal agitators" price_band: "$$ ($5–20 per item, typical US retail, October 2026)" manufacturer: "Pilot Corporation (Japan); sold in the US by Pilot Corporation of America" model: "CON-40" mpn: "CON-40" gtin: "4902505515330" url: "https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002532" --- # Pilot CON-40 Converter: Capacity, Fit & Filling > The Pilot CON-40 is Pilot's small twist-piston converter for its cartridge fountain pens, such as the Metropolitan, Kakuno and Prera. Pilot Japan lists it at 60 mm long, 7.2 mm across and 0.4 ml. Four metal agitators inside break up air bubbles, and Pilot says the air left after filling is normal. - URL: https://stationerytimes.com/guides/pilot-con-40-converter/ - Category: Accessories - Author: Ellis Penhale - Published: 2026-10-22 - Updated: 2026-10-22 ![Pilot CON-40 converter drawn to scale at 60 mm, with an inset of its metal agitators](https://stationerytimes.com/images/raster/pilot-con-40-converter-16x9.png) *The CON-40 at Pilot's 60 mm (drawn at 1 mm = 8 px; part lengths by eye).* Original drawing (SVG): . Drawings © 2026 Stationery Times, reusable with credit under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ## Product facts | Product | Brand | Brand origin | Made in | Material | Released | Price range (typical US retail, October 2026) | |---|---|---|---|---|---|---| | Pilot CON-40 converter | Pilot (by Pilot Corporation (Japan); sold in the US by Pilot Corporation of America) | Japan | Not stated | Clear plastic barrel, plastic twist knob and piston, metal agitators | – | $$: $5–20 per item | - Made in (Pilot CON-40 converter): Not stated. Pilot Japan's web catalog entry for the CON-40 lists size, capacity, JAN and price but no country of manufacture, and the Goulet Pens and Amazon listings we read don't give one either. Source: https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002532 ## Key takeaways - Pilot Japan lists the CON-40 at 60 mm (2.4 in) long and 7.2 mm across at its widest. - Pilot gives its ink capacity as 0.4 ml, about half the 0.8 ml often quoted for the LAMY Z28. - Pilot Japan's list price is ¥550 (about US$3.50) including tax; in the US it sits in our $$ band, $5–20. - Goulet Pens says 4 small metal agitators inside help break up air bubbles. - Pilot's Japanese FAQ says a converter that looks half full after a 0.4 ml fill is normal. ## What is the Pilot CON-40? **It is Pilot's twist-piston converter: a small refillable reservoir that replaces a Pilot cartridge so you can fill from a bottle.** Pilot Japan's catalog calls it a 回転式 (rotating) ink filler for cartridge fountain pens. Many US beginners meet it first, because it fits the [Pilot Metropolitan](https://stationerytimes.com/guides/pilot-metropolitan/) and [Pilot Kakuno](https://stationerytimes.com/guides/pilot-kakuno/). The single CON-40 had about 3,200 ratings on Amazon US and ranked #36 in Fountain Pens on October 22, 2026. ## Pilot CON-40 specs | Spec | Value | |---|---| | Maker | Pilot Corporation, Japan | | Model / JAN | CON-40 / 4902505515330 | | Mechanism | Twist piston (Pilot Japan) | | Size | 60 mm (2.4 in) long, 7.2 mm max across (Pilot Japan) | | Capacity | 0.4 ml (Pilot Japan); 0.61 ml max (Goulet) | | Inside | Four metal agitators (Goulet) | | Japanese list price | ¥550 (about US$3.50) incl. tax | | Price band | $$ ($5–20 per converter) | Pilot's rated 0.4 ml is the figure to plan with; Goulet's 0.61 ml is a measured maximum. ![Pilot CON-40 converter drawn to scale, 60 mm long and 7.2 mm across, with parts and key facts](https://stationerytimes.com/images/pilot-con-40-converter-parts.svg) *The CON-40's parts at Pilot's listed size; part lengths are by eye.* ## Why does the CON-40 look half full? **Because it pulls air out of the feed as it fills, and Pilot says that's normal.** Pilot's Japanese FAQ explains that the converter also sucks in the air in the feed's comb, ink and air channels, so the barrel can't fill completely, and plenty of air remains after the rated 0.4 ml. Goulet's reviewers complain about the same thing. To get a fuller fill, point the nib up after filling, turn the knob to push out the air until a drop appears, then dip and fill again. ## Which pens does the CON-40 fit? **Pilot's cartridge fountain pens.** Goulet says it fits all current Pilot and Namiki pens; our guides confirm it for these: | Pen | CON-40? | Notes | |---|---|---| | Pilot Metropolitan | Yes | Also takes the CON-B squeeze converter | | Pilot Kakuno | Yes | Pilot Japan also lists the CON-70N | | Pilot Prera | Yes | Pilot Japan puts one in the box | | Pilot Falcon, E95S | Yes | Also listed for the CON-70N | | Other brands | No | Pilot uses its own fitting | The [Pilot Prera](https://stationerytimes.com/guides/pilot-prera/) guide covers the boxed CON-40 in Japan. ## Which is better, the CON-40 or the CON-70? **The CON-40 is smaller and fits more pens; the CON-70 holds more but suits fewer.** Pilot's Japanese catalog lists both for some pens, such as the Kakuno and E95S, so check the listing for your pen before buying the bigger one. If you want more ink per fill in a CON-40 pen, refilling an empty Pilot cartridge with a syringe is the usual trick. A fresh [Pilot Namiki cartridge](https://stationerytimes.com/guides/pilot-namiki-ink-cartridges/) holds about 0.9 ml, per Goulet Pens. ## How long does a CON-40 fill last? **Not long: 0.4 ml is a few pages for most nibs, less with a broad or wet one.** That small capacity is the most common complaint in Goulet's reviews, where one buyer calls it "a reliable tool, though with a small capacity". Small fills have an upside. If you like to change inks often, a CON-40 lets you try a color without committing to a large fill, and it is quick to flush clean. If you write a lot, carry a spare Pilot cartridge refilled from your bottle, or choose a pen with a larger reservoir such as a piston filler. For more on the trade-offs, see our [how to clean a fountain pen](https://stationerytimes.com/guides/how-to-clean-a-fountain-pen/) guide, which covers flushing a converter between inks. ## How do you fill a CON-40? **Push it onto the pen, dip the nib, and twist the knob.** 1. Twist the knob until the piston is at the front. 2. Dip the whole nib in the ink, past the breather hole. 3. Twist back slowly to draw ink up. 4. Point the nib up, push out the air, and repeat if you want a fuller fill. Our [how to fill a fountain pen](https://stationerytimes.com/guides/how-to-fill-a-fountain-pen/) guide compares converters with cartridges and piston fillers. ## Where is the Pilot CON-40 made? **Pilot doesn't say.** It is a product of Pilot Corporation of Japan, but no factory country appears on Pilot's Japanese catalog entry or on the US listings we read. ## Frequently asked questions ### How much ink does the Pilot CON-40 hold? Pilot Japan lists 0.4 ml. Goulet measured up to 0.61 ml, so 0.4 ml is the practical fill and anything more is a maximum. ### Why won't my CON-40 fill all the way? Pilot's Japanese FAQ says the converter also draws in the air inside the feed, so it can't fill completely; a lot of air left after taking up the rated 0.4 ml is normal. ### Which pens does the Pilot CON-40 fit? Pilot's cartridge fountain pens, including the Metropolitan, Kakuno, Prera, Falcon and E95S; Goulet says it fits all current Pilot and Namiki pens. It doesn't fit other brands. ### What are the metal pieces inside a CON-40? Agitators. Goulet says the four small metal pieces help break up air bubbles to keep ink flowing. ### CON-40 or CON-70? The CON-70 is Pilot's larger push-button converter and holds more, but it is longer and doesn't fit every Pilot pen. Pilot's Japanese catalog lists both for the Kakuno and E95S, so check your pen's listing. ### Is the Pilot CON-40 made in the USA? No. It is a Pilot Corporation (Japan) product; Pilot's listing doesn't state the factory country. ## Sources - [Pilot (Japan): コンバーター CON-40 web catalog (JAN 4902505515330; ¥550 incl. tax; 回転式; 最大径φ7.2mm 全長60mm; インキ量0.4ml)](https://webcatalog.pilot.co.jp/products/DispDetail.do?volumeName=00004&itemID=t000100002532) - [Pilot (Japan): よくあるご質問 コンバーター40にインキが十分に吸入できません (air left after a 0.4 ml fill is normal)](https://www.pilot.co.jp/support/fountain/40.html) - [Goulet Pens: Pilot CON-40 Piston Converter (0.61 ml max; four metal agitators; fits current Pilot and Namiki pens; 130 reviews)](https://www.gouletpens.com/products/pilot-con-40-piston-converter) - [Amazon: Pilot Fountain Pen Ink Converter Screw Type (CON-40) (UPC 072838698100; 3.2K ratings, #36 in Fountain Pens, October 22, 2026)](https://www.amazon.com/dp/B019W0PO68)