Every Fenris cartridge is labelled with a code like 1209RLLT or 0805RSMT. It looks cryptic the first time you see it, but it's actually a compact spec sheet — gauge, needle count and grind type, all in one string. Once you know how to read it, you can compare any cartridge on the market at a glance.
Breaking down the code
Take 1209RLLT as an example:
- 12 — the gauge, expressed as a two-digit code (12 = 0.35mm diameter needles).
- 09 — the needle count in the group (9 needles).
- RLLT — the configuration: Round Liner, Long Taper.
So 1209RLLT is a 9-needle round liner, 0.35mm gauge, long taper grind. Change any one segment and you change how the cartridge performs.
Gauge: the needle diameter
Gauge controls how thick each individual needle is, which affects how much ink it holds and how it feels moving through skin. Across the Fenris range:
- 06 / 0.20mm — the finest gauge we carry, used for the RLLT 06/0.20mm. Built for hair-fine detail and ultra-precise linework.
- 08 / 0.25mm — the RLLT 08/0.25mm balances fine precision with more reliable ink flow than the 0.20mm.
- 10 / 0.30mm — our most versatile gauge, covering everyday lining (RLLT 10/0.30mm) through to realism shading (RMLT 10/0.30mm, RMMT 10/0.30mm).
- 12 / 0.35mm — the widest gauge in the range, built for bold lines and larger-scale coverage across liners, magnums and shaders.
As a rule of thumb: smaller gauge numbers mean finer needles for detail; larger gauge numbers mean thicker needles for bold work and coverage.
Needle count: how much surface you're covering
The count is simply how many needles are grouped in the cartridge. A 3-needle liner (like 1203RLLT) gives you a tight, precise line. Move up to a 9 or 14-needle configuration in the same family and you're covering far more surface per pass — useful for bolder outlines or faster fills. On magnums and shaders, higher counts (we go up to 23 needles on the RMMT 12/0.35mm) mean more ink laid down per stroke, which is what large-scale shading and colour work needs.
Higher count isn't automatically "better" — it's a trade-off between coverage speed and control. A single artist might use a 3-needle liner for detail and a 19-needle magnum in the same session, on the same piece.
Configuration: what the letters mean
| Code | Full name | Best for |
|---|---|---|
| RL | Round Liner | Outlines, linework |
| RM | Round Magnum | Shading, colour fill, blending |
| RS | Round Shader | Soft shading, colour packing |
| LT | Long Taper | Softer transitions, more control |
| MT | Medium Taper | Faster saturation, bolder packing |
(For more on Long Taper vs Medium Taper specifically, see our companion guide on choosing the right grind.)
Putting it together
Once the code clicks, you can size up any cartridge in seconds. 1219RMLT? 0.35mm gauge, 19-needle round magnum, long taper — built for big, soft realism fills. 0603RLLT? 0.20mm gauge, 3-needle round liner, long taper — built for the finest detail work you can do.
Every Fenris cartridge is EO gas sterilised and boxed in 20s, so once you've found the codes that suit your style, restocking is just a matter of matching the string on the box. If you're still narrowing things down, our Sample Box is the cheapest way to test a spread of gauges and counts before committing to full boxes.
