MEDICAL-GRADE MANUFACTURING

High-Flow Hollow Round Liner Cartridges for Bold, Consistent Outlines

At R&G Bio, we manufacture disposable tattoo needle cartridges for tattoo shops, distributors, and permanent makeup artists around the world.

Our Hollow RL cartridges are designed for artists who want a liner with a more open structure and strong ink delivery. The hollow needle arrangement supports smooth flow and bold line work, making it a dependable choice for outlines that need both clarity and impact. It keeps the needle stable, feeds ink consistently, and helps the line move cleanly through the skin.

Each cartridge has a membrane to stop backflow. They’re individually sealed and EO gas sterilized, with batch numbers for full traceability. Needles are 316L surgical stainless steel, housings are medical-grade polymer, and the whole operation runs inside ISO Class 7 cleanrooms under ISO 13485.

Bold Line Performance

Enhanced Ink Flow

EO Sterilized

OEM/ODM Ready

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Model Reference

1
For example – 0809RL

08 – Needle Diameter (Gauge)
09 – Needle Count
RL – Needle Configuration

2
Needle Diameter (Gauge)

08 = #8 (Bugpin, approx. 0.25 mm)
10 = #10 (Standard, approx. 0.30 mm)
12 = #12 (Standard, approx. 0.35 mm)

3
Needle Count

01 / 03 / 05 / 07 / 09 / 11 / 13 / 14 / 15 / 17 / 18 / 23 / 27

4
Needle Type

RL = Round Liner
RS = Round Shader
M1 = Magnum (Double Stack)
RM = Round Magnum

Tight RL

Hollow RL

Bugpin RL

0801RL

0809RL

0801RL

0803RL

0811RL

0803RL

0805RL

0814RL

0805RL

0807RL

1009RL

0807RL

1001RL

1011RL

0809RL

1003RL

1014RL

0811RL

1005RL

1209RL

0814RL

1007RL

1211RL

0818RL

1201RL

1214RL

1203RL

1205RL

1207RL

➡️ View Full Model List

What Are Hollow Round Liner Cartridges?

🔬 Needle Structure

Hollow Round Liner cartridges use a modified circular configuration where the center of the needle grouping is intentionally left more open. This creates a slightly looser structure compared to standard liners, allowing ink to flow more freely through the grouping while maintaining an overall round formation.

The open center design changes how ink is distributed into the skin, often resulting in smoother flow and a slightly softer line edge. While still capable of producing solid outlines, Hollow RL cartridges offer a different balance between structure and flow, making them distinct from tightly packed liner configurations.

Primary Uses & Applications

Bold Outlining: Building strong outlines with a slightly more open structure for smooth ink delivery.

Visible Contour Work: Defining shapes and borders clearly in designs that need a stronger line presence.

Decorative Line Work: Creating clean ornamental lines, stylized edges, and pattern-based elements.

Balanced Precision Lining: Offering a mix of line control and flow for artists who prefer a more open round liner feel.

Common Hollow RL Configurations

* 1RL – “1” indicates Needle Count

1RL

Fine Detail with Enhanced Flow

3RL

Smooth Thin Lines

5RL

Balanced Outlines with Strong Ink Delivery

7RL

Bold Flowing Lines

9RL

Heavy Outlines with Saturated Ink Output

Technical Specifications

Material

316L Medical Stainless Steel

Needle Diameter

08 (0.25mm) / #10 (0.30mm) / #12 (0.35mm)

Taper Length

Short (2.0–2.5mm) / Medium (3.5mm) / Long (5.5mm)

Safety Feature

Patented anti-backflow membrane

Sterilization

EO Gas, individually blister packed

Packaging

20 pcs/box (standard) / Custom OEM

Bold Outlining tattoo

Traditional tattoo

Hollow RL vs Tight RL vs Bugpin RL Comparison

Aspect

Tight RL

Hollow RL

Bugpin RL

Definition

Closely packed pins for maximum precision.

Open/hollow center for increased ink flow.

Defined by thinner needle diameter (#08 or #10).

Feel

Firm, compact, and highly controlled.

Looser internal layout; less resistance.

Slimmer pins; feels lighter and softer.

Gauge

Typically #08, #10, or #12.

Usually #12 (0.35mm).

Primarily #08 (0.25mm) or thinner.

Ink Flow

Restricted and focused; steady delivery.

High flow; supports bold, smooth movement.

Lighter deposition; easy to layer details.

Line Style

Sharp, clean, and well-defined.

Bold, thick, and high-impact.

Delicate, fine, and crisp.

Best For

Script, geometric, and technical linework.

Bold traditional work and thick outlines.

Ultra-detail, realism, and fine script.

Advantage

Maximum edge control and clarity.

Strong ink delivery without losing shape.

Reduces visual heaviness; great for micro-work.

Trade-off

Can feel too restricted if packed too tight.

Less suitable for ultra-fine precision.

Lacks the bold coverage of larger gauges.

Explore Different Cartridges

About R&G Bio

Built on Precision.
Trusted Globally.

01

Where Precision Meets Medical-Grade Standards

ISO 13485 certified facility with ISO Class 100,000 cleanrooms. 316L surgical steel, complete traceability.

02

End-to-End Manufacturing Control

From needle configuration to sterile packaging, every step is precision-controlled with automated assembly and batch tracking.

03

Meeting International Regulatory Standards

CE Mark, FDA Registered, KFDA Approved, ISO 13485, RoHS Compliant. Full documentation for global market entry.

04

Trusted Tattoo Needle Manufacturer Since 2009

15+ years serving 50+ countries with premium cartridge tattoo needles and flexible OEM/ODM solutions.

Premium Tattoo & PMU Supply
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FAQs

Hollow RL removes the center needle from a standard round liner configuration. That leaves a hollow core running through the middle of the grouping — a circle with an open center instead of a solid cluster.

That open center acts as an extra ink reservoir. As the needle group enters the skin, ink flows from the outer ring of needles and from the hollow middle simultaneously. The result: a bolder, more saturated line per pass using the same needle count as standard RL.

Three things stand out. First, more ink flow. The hollow center stores extra ink, so you dip less often and lay down more pigment per stroke. Second, fewer passes to achieve the same saturation. Third, less skin trauma because you are not going over the same area as many times.

For artists who do bold outlines or large-scale work, those fewer passes add up across a session. Less fatigue for you, less trauma for the client, and typically cleaner healing.

The line reads slightly bolder than standard RL of the same count and diameter. The hollow center pushes more ink into the skin, so the deposited line spreads a touch more on contact. Most artists describe a 5RL Hollow as sitting between a 5RL standard and a 7RL standard in visual weight.

If you want bold outlines without bumping up your needle count, Hollow RL gives you that extra density while keeping the grouping compact.

Yes, and that is where a lot of artists find its real value. The hollow core releases ink in a softer, more diffused pattern than a solid liner grouping. That makes Hollow RL useful for shadow fills, soft black-and-grey transitions, and styles that blur the line between lining and shading.

It will not replace a dedicated shader, but for artists who like to handle both tasks with one cartridge, Hollow RL covers both bases.

Hollow RL runs on any rotary or pen machine that takes standard cartridges. The open center means slightly less surface resistance than a solid grouping of the same count, so the needle cycles with less drag.

Most artists run Hollow RL at their standard lining voltage. If anything, you can drop it slightly because the needle moves more freely and deposits ink more efficiently. Test on practice skin first to find your sweet spot.

Hollow RL comes in counts from 3RL to 14RL, across all three diameters: #08 (0.25 mm), #10 (0.30 mm), and #12 (0.35 mm). The 5RL, 7RL, and 9RL Hollow configurations are the most popular for general tattoo work.

For bold traditional outlines, 9RL or 11RL Hollow in #12 delivers heavy lines with minimal passes. For softer, more nuanced work, 5RL Hollow in #10 gives you a line that sits between fine and bold.

No. We built a proprietary stabilization system into every Hollow RL that maintains needle alignment throughout the stroke. The open center does not compromise structural integrity. Needles stay true, lines stay straight.

Our membrane system also prevents backflow, so the open center creates no additional contamination risk. Safety standards match every other cartridge in our lineup.

CE Mark, FDA Registered, KFDA Approved, ISO 13485, RoHS Compliant. We ship the paperwork you need for wherever you’re working.

Private labeling, custom needle setups, OEM/ODM. Drop us a line and tell us what you need.

OEM / ODM SERVICES

Contact us for wholesale pricing and custom configurations
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