Everything You Always Wanted to Know About Refills* (*But Were Afraid to Ask) 2

Retro 51

The stationery community has been writing a few Retro 51 articles on stationery.wiki. When I tried to make the information in these articles semantic1 I came across a few issues.

One issue is related to Retro 51’s refills, one related to their categories, lines and editions. Luckily the users in The Pen Addict’s Slack channel are extremely helpful and knowledgeable when it comes to Retro 51 so the confusion with Retro 51’s series, categories, lines etc has been solved.

The other issue, relating to their refills, took me a while to figure out. This was probably not helped by the fact that I don’t own a Retro 51.

The short answer is: I think Retro 51’s rollerballs accept standard G2 refills, which means you can turn them into rollerball, gel or ballpoint pens.

Here are some of the bits of information I found along the journey. They might be old information for you, but since I am more into pencils and fountain pens than refillable non-disposable rollerballs a lot of this was new to me.

ISO standard

Refills are standardised in the ISO standard 12757.

ISO 12757-1 is for general use, i.e. there are not too many demands on the ink.

ISO 12757-2 is for documentary use, i.e. for writing documents that are required as evidence and the standard also looks into things like how the ink is coping with bleach, etc.

Refill overview


There seems to be contradictory information on the web when it comes to the G2 refills. This is probably not helped by the fact that Pilot has a pen called the G2. Based on what I have seen so far G2 and RB refills tend to get confused.

The G2 standard seems to have its origin in Parker’s Jotter refills, which came out in the 1950s.

I have produced a little table with further information about these refills. It also includes average writing length per refill based on the information by Premec. Other refills may vary.

TypeDiameterLengthNameAvg writing lengthInk charge
D1 mini
2.3557.1 or 67.0multicolor
350 m0.1 g
Japan Style2.9-3.0variable600 m -
2000 m
0.22 g - 0.32 g
Spezial3.061.0 or 66.5
X103.05106.8ballpoint standard
X203.05106.8ballpoint standard
large capacity
0.8 mm:
2200 m
1.0 mm:
1900 m
0.4 g
stick refills
1700 m0.375 g
large capacity
G26.0098.1ballpoint / gel
large capacity
0.7 mm:
400 m (gel)
5000 m (oil based)
0.7 g (gel)
1.1 g (oil based)
RB6.30110.0standard rollerball0,5 mm: 500m
0.7 mm: 400m
0.8 g
130.8 (stick)
110.5 (retractable)
gel refill0.7 mm:
450 m (stick)
600 m (retractable)
0.7 g (stick)
0.9 g (retractable)

For more information about refills see The Well-Appointed Desk’s Epic Refill Reference Guide and The Refill Finder.

The diagram is from Qniemiec, translation by Francis Flinch and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

  1. To allow exciting queries like the one producing this table. []

Leave a comment

Your email address will not be published. Required fields are marked *

2 thoughts on “Everything You Always Wanted to Know About Refills* (*But Were Afraid to Ask)

  • Ana

    The confusion comes from the G2 term. Some places (shops, online vendors, etc) use it to differentiate the Parker-style refills from the regular European standard rollerball refills which often get referred to as G2s, not to be confused with the Pilot G2.

    That said, Retro 51s accept Schmidt 8126/8127 and Parker-style refills only, without an adapter. See the bottom of the Refill Guide for links to Tofty’s handy dandy adapters.