A cartridge code like 1207RL is three facts in a row: the needle gauge, the number of needles, and how they are grouped. Once you read it that way, every box on the shelf says what it is for. This note covers the grouping, the last part of the code. Gauge and taper have their own note.
The four groupings
| Code | Name | How the needles sit | What it is generally used for |
|---|---|---|---|
| RL | Round liner | Bundled tight in a circle, soldered close to the tip | Lines and fine detail; the tighter the bundle, the crisper the line |
| RS | Round shader | Bundled in a circle, soldered further from the tip so the needles spread slightly | Small shading, soft fill in tight areas, some lining styles |
| M1 | Weaved magnum | Two staggered rows, flat | Shading and colour packing over larger areas |
| RM | Curved (round) magnum | Two staggered rows with the outer needles shorter, so the tip is arched | Shading that follows the skin's curve; softer edges than a straight magnum |
The number before the letters is the needle count: 3RL is three needles, 7RL is seven, 9M1 is nine in two rows. The two digits before that are the gauge. So 1207RL is seven #12 needles in a tight round bundle, 1209RM is nine #12 needles in a curved magnum.
What changes when you change the count
More needles means a wider mark and more ink delivered per pass, which is why liners run small counts and magnums run large ones. It also means more surface area entering the skin at once, which changes how the machine feels and how the skin responds. Most artists settle on a short list of configurations they trust and keep the rest for specific jobs. A sensible stock is the short list in depth, not the whole catalogue in single boxes.
Reading a cartridge against its spec sheet
A spec sheet should tell you at least the gauge, the count and the configuration, the pack size, and what is sterile and single-use. On our sheets those rows are stated when we can document them and marked confirmed on arrival of first lot when we cannot yet. A row that says "long taper" without a length, or "medical grade" without a standard, is not a specification; it is a mood. Ask for the number.
Our cartridges
The Cartridge system carries liners, shaders and magnums in boxes of twenty. Each box is one lot, and the lot number is recorded here when it arrives, so a box can be traced back to its sterilisation record. The Engine on your Studio page reads how fast each configuration goes and proposes the next box before the last one runs out.