Cartridge Needle Sizes: How to Read the Codes

A cartridge label such as 1007RL packs four facts into seven characters: the needle diameter, the number of needles, the grouping and, on many packs, a taper that is printed elsewhere. Once you can decode those facts, comparing cartridges across brands becomes a matter of reading specifications instead of guessing. This guide explains each part of the code, shows how groupings differ, and lists what to check before you order. It is written for working artists and studio buyers by BVShop (Beauty Visit Shop), a professional supplier of tattoo, PMU and beauty supplies.

One point first: no single size is correct for every job. Diameter, count, grouping and taper interact with your machine, your technique and the skin in front of you. This article explains the vocabulary so you can choose; it does not prescribe settings.

Key takeaways

• A typical cartridge code reads in order: diameter, needle count, grouping. In 1207RL, 12 is the diameter class, 07 the needle count and RL the round liner grouping.
• Diameter and count are separate choices. A 1207RL and a 1007RL have the same count but are not interchangeable, because the thicker needles change how the cartridge behaves.
• Grouping letters (RL, RS, M1, RM, and curved magnum variants) describe how the needles are arranged, not how many there are.
• Taper and tip finish are often printed separately from the main code, and naming varies between manufacturers. Check the product page or the manufacturer’s documentation.
• Fit matters as much as size. Confirm that the cartridge system matches your machine or pen before you buy in quantity.

Table of Contents

• What a cartridge is, and why the label matters
• Reading the code: diameter, count, grouping
• Needle groupings: RL, RS, M1, RM and curved magnum
• How needle count changes the cartridge
• Taper and tip: the part the code often leaves out
• Do all cartridges fit all machines?
• Quality checks when you open a box
• Hygiene and legal context
• Choosing cartridge sizes by situation
• Shop cartridges at BVShop
• A short checklist before you order
• FAQ
• Sources

What a cartridge is, and why the label matters

A tattoo cartridge is a disposable module: the needle group sits inside a plastic housing, usually with a membrane that separates the needle bar from the machine’s grip and drive. Modern studios widely work with cartridges instead of soldering bar needles, because the housing is single use and the setup is faster.

The label is how you compare products. Two cartridges that both say “5RL” can still differ in diameter, taper, tip shape and how tightly the needles are soldered. That is why the code is a starting point and the manufacturer’s specification sheet is the final word.

If you want a wider look at how machines, inks and cartridges fit together in a studio setup, our overview of tattoo machines, inks and cartridges for studio work covers the system as a whole.

Reading the code: diameter, count, grouping

Most cartridge codes follow the same structure that bar needles used for years.

1. Diameter. The first two digits. Common classes are 08, 10 and 12, usually corresponding to roughly 0.25 mm, 0.30 mm and 0.35 mm needles. Some manufacturers also offer other classes, such as 0.40 mm, and a few print the millimeter value directly instead of the class number.
2. Needle count. The next digits give how many needles are in the group. 07 means seven needles; 11 means eleven.
3. Grouping. The letters at the end describe the arrangement: RL for round liner, RS for round shader, M1 for single-stacked magnum, RM for round magnum, and so on.

So 1207RL is a seven-needle round liner in the 0.35 mm class. 1005RS is a five-needle round shader in the 0.30 mm class. Some brands drop the leading zero or write the diameter as a plain number (for example 5RL with the diameter listed in the product title), so read the title and the specification together.

Diameter classes at a glance

The descriptions are common trade shorthand, not rules. Two artists with different hand speeds and machines will reach different conclusions about the same cartridge.

A useful way to think about it: diameter is a trade-off between precision and ink delivery. Thinner needles are associated with finer detail; thicker needles carry more pigment through the same group. A 1207RL and a 1007RL have the same count but behave differently, so treat them as different products, not as a size swap.

For a deeper look at the diameter classes and how they relate to the older bar-needle system, see our companion piece on tattoo needle sizes.

Needle groupings: RL, RS, M1, RM and curved magnum

The letters describe geometry. The same needle count can be arranged in different shapes, and the shape changes how the group meets the skin and how pigment flows.

The difference between RL and RS is arrangement, not count. A round liner places the needles close together for a crisp line, while a round shader spaces them more loosely so the pigment spreads in a softer way. A “tight” liner variant, where offered, narrows the group further.

Names are not perfectly standardized. One brand’s “curved magnum” may be another’s “soft edge magnum,” and some brands add proprietary suffixes. When a listing uses a name you do not recognize, look for the needle count, row arrangement and diameter in the description.

Liners and shaders from the BVShop range

If you are comparing round liners, these listings show how different brands present the same grouping: Skin Monarch Luxury round liner cartridges, Peak Blood round liner cartridges, Vertix round liner tight cartridges and Magic Moon round liner needle cartridges.

For round shaders, see Skin Monarch Luxury round shader cartridges, Vertix round shader cartridges and the DA VINCI V2 round shader cartridge needles. Available configurations differ per product, so read each page for the diameters and counts currently offered.

For stipple-style work, the Peak dotwork ink drawing cartridge is a specialized option. Check its page for its configuration before you assume it behaves like a standard liner.

How needle count changes the cartridge

Count is the number most buyers notice first, and it is easy to misread. More needles do not automatically mean a bigger line or a better shader; the effect depends on grouping and diameter.

• Round liners range from very small groups (3RL, 5RL) to larger ones (7RL, 9RL and beyond). A small group is commonly chosen for fine line and detail, a larger group for bolder outlines. Because the needles are tightly packed, adding needles widens the group.
• Round shaders use the same counts, but the looser arrangement means the footprint is wider than a liner with the same number.
• Magnums run to higher counts, typically from 5 up through the teens and beyond, and the row length grows with each needle. The count here is a rough guide to how wide the working area is.

A practical example: you want to compare a 1005RL with a 1007RL. Both are in the 0.30 mm class, so the main difference is two extra needles in the group. That changes the footprint and the amount of pigment carried, which is why many artists keep a few counts in each grouping instead of one favorite.

Taper and tip: the part the code often leaves out

Taper is the length of the narrowing section at the needle tip. A longer taper generally means a finer point leading into the skin; a shorter taper gives a blunter transition. Manufacturers use terms like standard, long and extra long, and sometimes a code such as LT or ELT, but the actual lengths are not identical across brands.

Professional artists often weigh taper and grouping tightness as heavily as the headline size, because these details affect how a line behaves and how the cartridge feels in the hand. Two cartridges with matching codes can differ here.

What to do about it:

• Read the taper name on the product page, and look for the length in millimeters if the manufacturer publishes it.
• Do not assume that “long taper” from one brand equals “long taper” from another.
• When you change brands, order a small quantity first, or a test set, before restocking.

A test set is a sensible way to do this, and it is why BVShop offers the Skin Monarch Luxury tattoo cartridges test set for artists who want to compare configurations before committing to a full box.

Do all cartridges fit all machines?

No. Cartridge fit is a compatibility question, not a size question. Most modern cartridges use a membrane system and a standard cartridge-style connection, but grip dimensions, needle bar attachment and stroke setup vary between machine makers. A cartridge that seats in one pen can feel loose, bind or change needle protrusion in another.

Before ordering a new brand:

1. Check whether the product page states which systems it is designed for.
2. Check your machine or pen manufacturer’s documentation for compatible cartridge types.
3. Open one cartridge and confirm that it seats firmly and that needle movement feels smooth.
4. Buy a small quantity first when the system is new to you.

This is also where tattoo machines and cartridges are best treated as a pair. If you are replacing both, shop them together and cross-check the specifications.

Quality checks when you open a box

Size codes tell you what the cartridge is meant to be. They do not tell you whether a given batch matches. Experienced artists tend to check a few things on arrival:

• Needle alignment. Look at the tip and confirm that the needles sit in the expected formation with no stray or crossed points.
• Grouping consistency. A 5RL that is tight in one batch and loose in the next will behave differently from session to session. Compare a few units from the same box.
• Movement. Press the plunger or bar gently and feel for smooth travel, without catching or wobble.
• Packaging. Confirm that sterile packs are sealed and intact, and check the lot number and expiry date printed on the pack.

Safety-oriented studios often add a membrane test. The idea is to verify that the barrier between the needle area and the machine does its job, so that pigment or fluids cannot travel back into the grip. In Europe, the relevant standard is EN 17169, and a cartridge manufacturer should be able to state whether its membrane design is intended to meet it. Ask the manufacturer for documentation instead of relying on a label alone, and follow the testing method your local health authority or training provider recommends.

Hygiene and legal context

Requirements differ by country and, in the US, often by state or county. Some jurisdictions require single-use sterile needles or cartridges for tattooing; for example, Polish health authority training materials on decontamination in tattoo studios state that disposable sterile needles or cartridges should be used. That is one country’s guidance, not a worldwide rule.

Whatever your location, confirm the rules with your local health department or licensing body, and keep the sterilization indicators and lot information from your packs for your records.

Choosing cartridge sizes by situation

These are starting points for building a shelf, not instructions for skin or technique.

A balanced starter shelf for a new studio usually holds a few liner counts, a couple of shader counts and one or two magnums, then grows according to what the artists actually use. Reorder the sizes that run out fastest, not the ones that look best on a chart.

Shop cartridges at BVShop

BVShop (Beauty Visit Shop) supplies professional tattoo, PMU, microblading and beauty products to artists and studios. Our tattoo supplies collection brings cartridges together with machines, power supplies, inks and accessories, so you can check compatibility in one place.

If you want to compare configurations before buying in quantity, start with the Skin Monarch Luxury tattoo cartridges test set. For line work, see the Skin Monarch Luxury round liner cartridges, and for soft-edge work, the Skin Monarch Luxury curved magnum cartridges. Prices, stock and shipping terms for your destination are shown on each product page.

A short checklist before you order

1. Decode the label: diameter, count, grouping.
2. Find the taper name and, if available, its length.
3. Confirm that the cartridge fits your machine or pen.
4. Check that the pack is sterile, single use and dated.
5. Ask the manufacturer for documentation when a claim matters to your licensing.
6. Order a test quantity before switching brands.

FAQ

What is the difference between a 10 and a 12 cartridge needle?

The number is the diameter class. A 10 is roughly 0.30 mm and a 12 roughly 0.35 mm, so a 12 is the thicker needle and carries more pigment per needle. They are not interchangeable at the same count, and the right choice depends on your machine, technique and the work. Check each manufacturer’s specification for the exact diameter.

What is the difference between RL and RS cartridges?

Both are round groupings, but a round liner packs the needles tightly for crisp lines, while a round shader spaces them more loosely for softer spreading of pigment. The count can be identical. Shader and liner variants from different brands may differ in tightness, so compare product pages.

Do all cartridge needles fit all tattoo pens?

No. Many cartridges use a similar membrane-style design, but grip dimensions, needle bar connection and stroke geometry vary between machines. Check the manufacturer’s compatibility information for both the cartridge and the machine, and test one cartridge before ordering a full box.

Is an 80/12 or 90/14 needle bigger?

Those numbers are sewing-machine needle sizes, not tattoo sizes, so they do not apply to cartridges. Tattoo cartridges use a diameter class such as 08, 10 or 12, which corresponds to roughly 0.25, 0.30 and 0.35 mm.

Sources

• Polish National Institute of Public Health: decontamination training materials for tattoo studios

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• DA VINCI V2 Magnum Cartridge Needles
• Tina Davies Needle Cartridges
• Kwadron Cartridges Sizes
• DA VINCI V2 Round Liner Cartridge Needles