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Pen Refills Explained: Formats, Codes and Swaps

By · Published · 7 min read

Compiled from 13 sources; we haven't tested these products ourselves yet. How we research

Quick answer

The refill, not the body, decides how a pen writes: its ink, ball size and line. Most refills fit only their own family, such as Jetstream SXR-7 or SXR-80, Zebra JF or uni Style Fit UMR-109; Parker-style G2 and D1 are shared formats. Check the maker's chart before swapping, because a near-fit can leak.

On this page10 sections
Nine pens in a row, each labelled with the refill it takes, with a close-up of an SXR-80-05 refill tip
Nine bodies, eight refill families: the label under each pen is what decides how it writes.

Products compared

  1. Parker Jotter stainless steel ballpoint with the point out, drawn to scale, with a close-up of the arrow clipNo. 1Parker Jotter Stainless Steel CT ballpoint pen$$$Read the guide →
  2. uni Jetstream Prime Twist Single 0.7 mm in Black drawn to scale, with its silver tip, ring and slit clipNo. 2uni Jetstream Prime Twist Single Ballpoint$$$Read the guide →
  3. uni-ball Jetstream RT 1.0 mm with the tip out, drawn to scale, showing its embossed grip and steel clipNo. 3uni-ball Jetstream RT Retractable Ballpoint$Read the guide →
  4. Navy uni Jetstream 4&1 multi pen with the blue ballpoint out, drawn to scale, with an end view of its slidersNo. 4uni Jetstream 4&1 Multi Pen$$Read the guide →
  5. uni-ball &knot in Lantern Orange, uncapped, with its magnetic cap, fabric tag and carabiner, drawn to scaleNo. 5uni-ball &knot Carabiner Ballpoint with Jetstream Ink$$$Read the guide →
  6. uni Style Fit 3-color holder in silver with the blue refill extended, drawn to scale, with the top end-onNo. 6uni Style Fit 3-color holder$$Read the guide →
  7. Pilot G2 0.7 mm Fine retractable gel pen with the tip out, showing its clear barrel and ribbed gripNo. 7Pilot G2 Premium Retractable Gel Pen$Read the guide →
  8. Zebra Sarasa Clip 0.5 mm retractable gel pen with the tip out, showing its binder clip and clear barrelNo. 8Zebra Sarasa Clip Retractable Gel Pen$Read the guide →
  9. Red Retro 51 Tornado Classic Lacquer rollerball, retracted, drawn to scale, with its knurled top insetNo. 9Retro 51 Tornado Classic Lacquer Rollerball$$$Read the guide →
ProductBrand originMade inPrice range
Parker Jotter Stainless Steel CT ballpoint penParkerUnited StatesFrance*Price range: $$$$20–75 per pen
uni Jetstream Prime Twist Single Ballpoint (0.38 / 0.5 / 0.7 mm; SXK-3000)uni-ballJapanJapan*Price range: $$$$20–75 per pen
uni-ball Jetstream RT Retractable Ballpoint (0.5 / 0.7 / 1.0 mm; SXN-210)uni-ballJapanJapan*Price range: $under $5 per pen
uni Jetstream 4&1 Multi Pen (0.38 / 0.5 / 0.7 mm + 0.5 mm pencil; MSXE5-1000)uni-ballJapanJapan*Price range: $$$5–20 per pen
uni-ball &knot Carabiner Ballpoint with Jetstream Ink (0.5 mm; SX-AK-05)uni-ballJapanJapan*Price range: $$$$20–75 per pen
uni Style Fit 3-color holder (UE3H-208) with Style Fit gel refills (UMR-109)uniJapanNot stated*Price range: $$$5–20 per pen
Pilot G2 Premium Retractable Gel Pen (0.38 / 0.5 / 0.7 / 1.0 mm)PilotJapanJapan*Price range: $under $5 per pen
Zebra Sarasa Clip Retractable Gel Pen (0.3 / 0.4 / 0.5 / 0.7 / 1.0 mm; JJ15)ZebraJapanJapan*Price range: $under $5 per pen
Retro 51 Tornado Classic Lacquer Rollerball (Red, VRR-1308)Retro 51United StatesTaiwan*Price range: $$$$20–75 per pen
Notes on these facts
  • Parker Jotter Stainless Steel CT ballpoint pen: Made by Parker Pen Company (part of Newell Brands). Made in France: Wikipedia's history says production moved from Newhaven, England, to Nantes, France, after Parker closed its English factory late in 2010, and that Jotters are now imprinted Made in France. PartsSource and Galaxus list France for item 1953170, and Sainsbury's and Bruneau for other stainless models. Parker's US, UK and French sites blocked our reader. Source. Price: example listing.
  • uni Jetstream Prime Twist Single Ballpoint (0.38 / 0.5 / 0.7 mm; SXK-3000): Made by Mitsubishi Pencil Co., Ltd.. Made in Japan: The Gentleman Stationer (US) and Hunter Paper Co. (UK) both say made in Japan, and unsharpen lists Japan as the country of origin. Mitsubishi Pencil's Japanese product page and press release don't state it. Source. Price: example listing. Released: Mitsubishi Pencil's February 7, 2018 press release gives the Japanese launch date; unsharpen lists 2017. The knock-action Jetstream Prime Single (SXN-2200) came out on October 15, 2014.
  • uni-ball Jetstream RT Retractable Ballpoint (0.5 / 0.7 / 1.0 mm; SXN-210): Made by Mitsubishi Pencil Co., Ltd.. Made in Japan: per US business-supplier spec sheets for items 62152 (0.7 mm black), 62153 (0.7 mm blue) and 73834 (1.0 mm red), all listing Japan; Unsharpen also lists Japan. uni's US store, uni-ball UK and Mitsubishi Pencil's Japanese site don't state it. Source. Price: example listing. Released: Mitsubishi Pencil's February 17, 2011 press release says the Jetstream Standard went on sale in Japan in July 2006; we found no separate US launch date for the RT.
  • uni Jetstream 4&1 Multi Pen (0.38 / 0.5 / 0.7 mm + 0.5 mm pencil; MSXE5-1000): Made by Mitsubishi Pencil Co., Ltd.. Made in Japan: The Journal Shop lists Japan as the country of origin for the 0.5 mm 4&1. Mitsubishi Pencil's Japanese product page and press releases don't state it. Source. Price: example listing. Released: Mitsubishi Pencil's February 17, 2011 press release says the Jetstream 4&1 first came out in November 2008.
  • uni-ball &knot Carabiner Ballpoint with Jetstream Ink (0.5 mm; SX-AK-05): Made by Mitsubishi Pencil Co., Ltd.. Made in Japan: Simple Paper (US) and Hunter Paper Co. (UK) both list it as made in Japan. Mitsubishi Pencil's Japanese product page and press release don't state the pen's country of origin; the SXR-80-05 refill package pictured on its &knot site is printed MADE IN JAPAN. Source. Price: example listing. Released: Japanese launch date from Mitsubishi Pencil's June 3, 2026 press release. uni's US store lists it as uniball &knot with JETSTREAM SXR-80-05 Ink; we found no separate US launch date.
  • uni Style Fit 3-color holder (UE3H-208) with Style Fit gel refills (UMR-109): Made by Mitsubishi Pencil Co., Ltd.. Country of manufacture not stated: Mitsubishi Pencil's Japanese Style Fit pages, its January 2026 press release and the Monotaro listings we read don't state a country of manufacture. Check the packaging. Price: example listing. Released: Mitsubishi Pencil's January 15, 2026 press release says the Style Fit series has been sold since 2009; we found no exact launch date.
  • Pilot G2 Premium Retractable Gel Pen (0.38 / 0.5 / 0.7 / 1.0 mm): Made by Pilot Corporation (Japan); sold in the US by Pilot Corporation of America. Made in Japan: per US retailer spec sheets (Stop & Shop, OnTimeSupplies for item 31171). Some grocery listings for a 4-pack say "Japan, USA", so origin may vary by pack. Pilot's US site doesn't state it in the sources we found. Source. Price: example listing.
  • Zebra Sarasa Clip Retractable Gel Pen (0.3 / 0.4 / 0.5 / 0.7 / 1.0 mm; JJ15): Made by Zebra Co., Ltd. (Tokyo); sold in the US by Zebra Pen Corporation. Made in Japan: per retailer spec sheets: FairPrice (Singapore) lists Japan for the 0.7 mm pen and the JF-0.5 refills, Carrefour UAE lists Japan for the Sarasa Push Clip, and SM Stationery (Philippines) says made in Japan. Zebra's Japanese and global product pages don't state a country of manufacture. Source. Price: example listing.
  • Retro 51 Tornado Classic Lacquer Rollerball (Red, VRR-1308): Made by Retro 1951, Inc. (Texas), a Writeside Holdings company. Made in Taiwan: per the Unsharpen pen database (country of origin Taiwan); eBay item specifics for Tornado models also give Taiwan, and a Peyton Street Pens listing says the components are made in Taiwan. Retro 51's own pages, Goulet Pens and Pen Chalet don't state a country in the pages we read on October 21, 2026. Source. Price: example listing. Released: Retro 51's Our Story page says Retro 1951 introduced the Tornado in 1997 and celebrated its 25th anniversary in 2022. This red Classic Lacquer listing went up on Retro 51's own shop in 2025; red was one of the three launch 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

  • Mitsubishi Pencil's refill chart lists three Jetstream refill lengths that don't swap: SXR-7 at 111.5 mm, the Parker-style SXR-600 at 98.2 mm and the multi-pen SXR-80 at 87.7 mm.
  • The metal SXR-600 follows ISO 12757-2 G2, Mitsubishi Pencil says; Parker says its own Quinkflow ballpoint refills are certified to ISO 12757-2.
  • D1 multi-pen refills are about 67 mm long: Zebra lists its 4C-0.7 at 67.0 mm and 2.4 mm across, and Mitsubishi its SXR-200 at 67.0 mm.
  • In Japan, a Zebra JF-0.5 refill lists at ¥88 (about US$0.60), two-thirds of the ¥132 (about US$0.80) Sarasa Clip it fits.
  • An SXR-80-05 refill lists at ¥110 (about US$0.70), about 3% of the ¥3,630 (about US$23) uni-ball &knot it fits.

Why does the refill matter more than the pen?

Because the refill holds the ink and the ball: it decides the line width, the ink type and how smoothly the pen writes, while the body is a case that holds it. Put a 0.38 mm gel refill in a body built for a 0.7 mm ballpoint and you have a different pen.

That is why one good body can last for years. The Jetstream 4&1 and the uni Style Fit are built around this idea, and many metal pens take a shared Parker-style refill.

This explainer uses the makers’ refill charts and our own guides; we haven’t run swap tests ourselves yet.

What are the main refill formats?

A few formats are shared between brands, but most refills fit only their own family. Lengths below come from the makers’ Japanese refill pages unless noted.

Format Example refill Length Ink Shared?
Parker-style (G2) Parker Quinkflow, uni SXR-600 98.2 mm (3.9 in), SXR-600 Oil, gel or rollerball Yes, many brands
D1 multi pen Zebra 4C, uni SXR-200, LAMY M21 67.0 mm (2.6 in) Mostly ballpoint Mostly
Jetstream single uni SXR-7 111.5 mm (4.4 in) Low-viscosity oil No
Jetstream multi uni SXR-80 87.7 mm (3.5 in) Low-viscosity oil No
Zebra gel JF-0.5 111.1 mm (4.4 in) Gel No
Style Fit UMR-109, SXR-89 98.6 mm (3.9 in), UMR-109 Gel or oil No
LAMY M16, M22 Not published Oil LAMY only

What does ISO 12757-2 have to do with it? ISO 12757-2 (1998) sets requirements for ballpoint pens and refills for documentary use, such as records that must stay legible for a long time. Mitsubishi Pencil’s chart says the SXR-600 conforms to ISO 12757-2 G2, and Parker says its ballpoint refills are certified to ISO 12757-2, which is why “G2” and “Parker-style” name the same format. It has nothing to do with the Pilot G2 gel pen.

Six pen refill lengths drawn to scale, from the Jetstream SXR-7 to D1-size refills
Six refill families to one scale; refills a few millimetres apart still don't swap.

Which refill does each pen take?

Each of our nine pens takes one family; only the Jotter, Prime Twist and Tornado use the shared Parker-style format.

Pen Stock refill Also fits, per maker or dealer Price band
Parker Jotter Quinkflow ballpoint Other Parker-style refills $$$
Jetstream Prime Twist SXR-600 Parker-style refills (dealers) $$$
Jetstream RT SXR-7 SXR-38, SXR-5, SXR-10 $
Jetstream 4&1 SXR-80 (0.38, 0.5, 0.7 mm) SXR-80-10, Lite touch, ZENTO $$
uni-ball &knot SXR-80-05 Other SXR-80 sizes, ZENTO $$$
Style Fit UMR-109 gel SXR-89 Jetstream, pencil unit $$
Pilot G2 G2 refill (BLS-G2 outside the US) Other Pilot G2-family pens $
Zebra Sarasa Clip JF Same JF size in Sarasa and Sarasa Grand $
Retro 51 Tornado Retro 51 capless rollerball Schmidt P8127 and P8126, Parker-style $$$

Gel pens follow the same rule. The uni-ball Signo 207 takes the UMR-87 in the US, and Mitsubishi Pencil’s gel chart lists the UMR-85N as the stock refill of the 0.5 mm Signo RT1 (UMN-155N-05).

How do you read a refill code?

Most codes are a family name plus the ball size, then a color code.

  • SXR-80-05: a Jetstream (SXR) refill for multi pens (80), 0.5 mm ball.
  • JF-0.5: Zebra’s gel refill in 0.5 mm; Zebra orders it by color as RJF5-BK (black) or RJF5-BL (blue).
  • BLS-G2-7-B: Pilot G2 refill, 0.7 mm, black. US packs use item numbers such as 77240 instead.
  • UMR-83 and UMR-85N: Signo gel refills in 0.38 and 0.5 mm in Mitsubishi Pencil’s chart.
  • LAMY M16: LAMY says the type is printed on the old refill; the tip width is a letter (F, M or B).

Does a refill hack work?

Only when the maker’s chart or a dealer confirms the fit. Mitsubishi Pencil’s Jetstream chart marks each pairing with four symbols: ◎ for the stock refill, ○ for a confirmed fit, △ for a fit judged from shape with a small size gap, and × for a refill that looks similar but may leak.

Mitsubishi Pencil also says not to cut a long refill to fit, because ink can leak from the cut end and the edge can damage a multi pen. It warns that other makers’ “compatible” refills differ slightly in size.

Shared formats aren’t exact either. The Bleistift blog measured 0.04 mm between a LAMY and a Zebra D1 refill, enough to keep the Zebra out of a LAMY 2000 multi pen.

Is a refill cheaper than a new pen?

For a cheap gel pen, only a little; for a $$ or $$$ body, by far. Japanese list prices, including tax:

Pen Pen price Refill Refill price Refill as share of pen
Sarasa Clip 0.5 ¥132 (about US$0.80) JF-0.5 ¥88 (about US$0.60) 67%
Jetstream 4&1 ¥1,100 (about US$7) SXR-80 ¥110 (about US$0.70) 10%
&knot ¥3,630 (about US$23) SXR-80-05 ¥110 (about US$0.70) 3%
Style Fit 3-color holder ¥220 (about US$1.40) UMR-109 ¥110 (about US$0.70) 50%

The shares are our arithmetic. Keeping a body you like is the stronger case, and it cuts waste; our sustainable pens vs disposable guide covers that side.

Which body is worth keeping?

Pick the refill you like first, then a body that takes it.

  • Jetstream fans: the 4&1 or &knot for SXR-80, the Prime Twist for a metal SXR-600.
  • Gel fans: Style Fit for mixing Signo colors, or a Sarasa Clip and a pack of JF refills.
  • Freedom to switch: a Parker-style body such as the Jotter or Tornado.

Frequently asked questions

Do Parker-style refills fit the Jetstream RT?

No. The RT takes the plastic SXR-7, which Mitsubishi Pencil lists at 111.5 mm; its Parker-style refill is the metal SXR-600 at 98.2 mm, made for the Jetstream Prime twist pens. The two lengths don't swap.

Can you put a gel refill in a ballpoint pen?

Sometimes, if the format matches. The uni Style Fit holder takes Signo gel and Jetstream ballpoint refills side by side, and Mitsubishi Pencil's chart lets the &knot take water-based ZENTO refills. Dealers say the Retro 51 Tornado takes any Parker-style refill, gel or ballpoint.

What do the last digits of a refill code mean?

Usually the ball size. SXR-80-05 is a 0.5 mm Jetstream, JF-0.7 a 0.7 mm Zebra gel and BLS-G2-7 a 0.7 mm Pilot G2 refill; a letter suffix such as -B or BK then gives the ink color.

Will any D1 refill fit any multi pen?

Not always. Cult Pens describes D1 as a standard pattern about 67 mm long and 2.3 mm across, but the Bleistift blog measured a LAMY M21 at 2.32 mm and a Zebra refill at 2.36 mm, and the Zebra one wouldn't go into a LAMY 2000 multi pen.

Which refill fits LAMY ballpoints?

The LAMY M16. LAMY's German site says every M16 fits LAMY ballpoints and lists it at €4.10 (about US$4.60); the compact M22, at €3.90 (about US$4.40), is for the LAMY pico and scribble.

Is it safe to cut a long refill to fit a shorter pen?

Mitsubishi Pencil says no: ink can leak from the cut end, and in multi pens the cut edge can damage the mechanism. It also warns that other makers' look-alike refills differ slightly in size and can cause problems.

Are US Pilot G2 refills different from BLS-G2 refills?

They are sold under different codes. In the US Pilot sells G2 refills in 2-packs by item number, such as 77240 for 0.7 mm black; elsewhere the same sizes carry BLS-G2 codes such as BLS-G2-7.

Sources (13)

  1. 三菱鉛筆: ジェットストリーム替芯 互換表 (Mitsubishi Pencil Japan, Jetstream refill compatibility chart, PDF dated June 24, 2026, read in full: SXR-80 87.7 mm, SXR-7 111.5 mm, SXR-200 67.0 mm, SXR-600 98.2 mm and ISO 12757-2 G2; ◎ ○ △ × symbols; SX-AK-05 and MSXE5-1000 rows)
  2. 三菱鉛筆: ゲルインクボールペン替芯 互換表 (Mitsubishi Pencil Japan, gel refill compatibility chart, PDF dated June 24, 2026, read in full: UMR-82, UMR-83, UMR-85N, UMR-87E; Style Fit UMR-109 and SXR-89)
  3. 三菱鉛筆: 違う芯を入れたい [ボールペン] (Mitsubishi Pencil FAQ, read in full: cutting refills, other makers' refills)
  4. ゼブラ: ジェルボールペン替芯 (Zebra Japan gel refill page, read in full: JF-0.5 ¥88, 111.1 mm, 6.1 mm, fits Sarasa Clip 0.5, Sarasa 0.5, Sarasa Grand 0.5; RJF5 color codes)
  5. ゼブラ: 油性ボールペン替芯 (Zebra Japan oil-based refill page, read in full: 4C-0.7 ¥88, 67.0 mm, 2.4 mm)
  6. ISO 12757-2:1998 Ball point pens and refills, Part 2: Documentary use (DOC)
  7. Parker: Quinkflow ballpoint refill (all Parker ballpoint refills certified ISO 12757-2; page blocked our reader, read via search listing)
  8. Cromwell: Parker Quink Flow ballpoint refill, fine blue, 1950368 (ISO 12757.2 certified)
  9. LAMY (Germany): Ersatzminen (refill guide: every M16 fits LAMY ballpoints; read the type name on the old refill)
  10. LAMY (Germany): LAMY M 16 Kugelschreibermine (€4.10)
  11. LAMY (Germany): LAMY M 22 Kugelschreibermine (compact refill for LAMY pico and scribble, €3.90)
  12. Cult Pens: D1 multipen refills (67 mm long, about 2.3 mm across)
  13. Bleistift: D1 ≠ D1 (May 2021; LAMY M21 2.32 mm, Zebra JSB 2.36 mm, uni SXR-200 2.33 mm measured with calipers)

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