FK Irons (Fallen Kings Irons) is one of the world's leading manufacturers of tattoo machines and tattoo equipment. Founded in 2007, FK Irons is the first choice of many top tattoo artists. Founder Gaston Siciliano has worked daily to incorporate modern technology into the machine for the benefit of the artist to earn this respect.
FK Irons is also a co-sponsor of the Hope Against Cancer Foundation. There, events are given to children with cancer to give them a little joy.
The Flux Max Power Bolt 2.0 from FR Irons remembers your working style. It offers you more control, more innovation and more comfort. The machine adapts, so you can make full use of your skills. It recognizes the colors you use, the settings and the pressure you apply. Tattooing is much more pleasant and uncomplicated.Flux Max can be combined with all standard cadridges and existing grips, powerbolts and the Killersswitch from FK Irons.the machine is available with 3.2 mm, 4.0 mm and 4.5 mm stroke.Technical details:Handle with 38 mm diameterup to 10 hours battery life (depending on power level)Integrated timerStroke: 3.2 mm - 4.0 mm - 4.5 mm Device incl. battery: 205gMade in USA2 hours charging time when using the supplied USB-C charging cable
FK Irons One Adjust – Wireless tattoo machine with adjustable stroke | Premium wireless tattoo pen
FK Irons One Adjust – The revolution in wireless tattoo technology
Imagine being able to switch from precise linework to soft shading in the middle of a session – without changing machines, without switching off, without interruption. With the FK Irons One Adjust, that's exactly what happens. This wireless tattoo machine sets new standards and combines uncompromising flexibility with proven FK Irons quality.
Unique stroke adjustment during operation
At the heart of the One Adjust is patented stroke adjustment technology. You can adjust the stroke during a session—effortlessly, without missing a single stroke. Whether you're working with fine lines, rich color packing, or delicate shading, one setup covers it all. No more machine changes, no more cam swaps, no more compromises. The One Adjust adapts to your style, not the other way around.
Wireless freedom for marathon sessions
With two interchangeable, rechargeable batteries, you can work for up to 12 hours without interruption. The large battery provides up to 6.5 hours of power, the smaller one another 5.5 hours. Thanks to the included dual-slot charger, you always have a full battery at your fingertips. While you're tattooing, the spare battery charges—for true nonstop performance.
Technical specifications
Category
Details
Lift adjustment
Infinitely adjustable during operation (patented technology)
Power supply
Wireless with rechargeable drop-in batteries
Battery type
2x Panasonic NCR 18500A (premium quality)
Battery life
Up to 6.5 hours (depending on settings)
Short battery life
Up to 5.5 hours (depending on settings)
Total runtime
12+ hours with both batteries
Voltage range
5-12 volts
Voltage adjustment
Adjustable in 0.5V increments
Charger
Dual-slot charger (both batteries can be charged simultaneously)
Battery replacement
Quick-Twist system – change in seconds
Operation
3-button system (up/down/power)
LED display
Color-coded voltage display (flashes in 0.5V increments)
Handle
Ergonomic, with click grip Needle depth adjustment
Grip compatibilityAll modular FK grips (including Disposable grips)
Needle compatibility
Compatible with most standard needle cartridges
Weight
Lightweight design for fatigue-free working
Manufacturing
Designed, developed, and manufactured in the USA
Material
Highest quality steel available, extremely robust
Transport
Premium travel case with custom-fit protective foam
Warranty
2 years (for purchases made on or after January 1, 2023)
Scope of delivery
 
Position
Description
FK One Adjust machine
Fully assembled and ready to use
2x batteries
1x large battery (6.5 hours) + 1x small battery (5.5 hours)
Dual charger
Charging station for both batteries with LED charging indicator
Power cord
Special cable for charging station (use only this cable!)
Travel case
High-quality case with custom-cut protective foam
User manual
Detailed instructions for setup and maintenance
Areas of application & fields of use
 
Technology
Suitability
Advantages
Linework
⭐⭐⭐⭐⭐
Precise control thanks to adjustable stroke
Shading
⭐⭐⭐⭐⭐
Smooth transition from hard to soft possible
Color packing
⭐⭐⭐⭐⭐
Optimal saturation with minimal skin trauma
Portrait work
⭐⭐⭐⭐⭐
Finest nuances thanks to variable settings
Traditional
⭐⭐⭐⭐⭐
Powerful lines, then directly to shading
Realism
⭐⭐⭐⭐⭐
Perfect gradations without changing machines
Black & Gray
⭐⭐⭐⭐⭐
From deep black to delicate shades of gray
Guest Spots
⭐⭐⭐⭐⭐
Compact, securely packaged, versatile
Conventions
⭐⭐⭐⭐⭐
Wireless, long battery life, no setup hassle
Operation & features
 
Feature
Function
Benefit
Stroke Adjustment
Adjust stroke during operation
No interruption of the session necessary
Quick-Twist Battery
Battery replacement by turning
Replacement in seconds without tools
Power Disconnect
Deactivate battery during transport
No accidental switching on in the case
LED voltage display
Color-coded voltage display
See the correct setting at a glance
Click-grip adjustment
Adjust needle depth on the grip
Precise adjustment without dismantling the machine
3-button control
Simple up/down/power operation
Intuitive control, no complex menus
Dual-slot charging
Charge both batteries simultaneously
Always have a full spare battery ready
Battery indicator
LED shows charge status
Blue = fully charged, no surprises
Comparison: One Adjust vs. Standard Machines
Aspect
FK One Adjust
Conventional machines
Stroke adjustment
Adjustable during operation
Machine replacement or cam change required
Setup time
Set once, cover everything
Prepare multiple machines
Flexibility
Unlimited – all styles with one machine
Limited to fixed stroke
Workflow
Uninterrupted
Frequent machine changes
Mobility
Wireless, 12+ hours
Wired or shorter battery life
Investment
A premium machine
Multiple machines for different techniques
Universally applicable—designed for every style
The One Adjust was designed for versatility. It works independently as your only tool or integrates seamlessly into your existing FK Irons setup. From traditional linework to modern coloring to the finest portrait details, this machine masters every technique. Its adaptability gives you the freedom to tackle any project for any client.
Developed by professionals, built for professionals
Top artists worldwide have contributed to its development and confirm: The FK One Adjust has the potential to set a new industry standard. The ability to adjust the stroke length to your client's individual skin type makes the decisive difference between good and exceptional results. Artists report faster color saturation, fewer passes required, and thus reduced skin trauma.
Ergonomics meets American engineering
Designed, developed, and manufactured in the USA, the One Adjust embodies the precision and quality that FK Irons stands for. The ergonomic design ensures fatigue-free working, even during the longest sessions. Compatible with most standard needle cartridges, it integrates seamlessly into your existing workflow.
Why choose the FK One Adjust?
Patented technology: Globally unique stroke adjustment during operation
Maximum runtime: Up to 12+ hours of cordless power with dual battery system
All-in-one solution: One setup for all techniques—from powerful lining to delicate shading
Artist-approved: Developed in collaboration with world-leading tattoo artists
Made in the USA: Premium quality and reliability you can count on
Investment security: 2-year warranty and proven FK Irons quality
Studio & Travel Ready: Perfect for your home studio and guest spots
Time saving: Fewer machine changes = more time for tattooing
Ideal for:
Established artists who want to maximize their efficiency
Versatile tattoo artists who have mastered different styles
Studios with a high volume of sessions
Artists who frequently work at guest spots or conventions
Professionals who value the highest quality and flexibility
The FK Irons One Adjust is more than a machine—it's a game changer. It gives you the tools to work at the highest level without being limited by technical constraints. If you're ready to expand your creative freedom and maximize your efficiency, the One Adjust is the machine you've been waiting for.
Quality promise
Since 2007, FK Irons has stood for innovation and precision in the tattoo industry. Founded by Gaston Siciliano, a tattoo artist and design engineer, the brand has become synonymous with uncompromising quality. Every machine is manufactured to the highest standards and undergoes rigorous quality controls. The result: machines that work as hard as you do.
Experience what is possible when innovation meets craftsmanship. The FK Irons One Adjust – built to adapt, built to perform, built to work as hard as you do.
FK Irons One Update - Wireless Tattoo Machine, 3 Finishes, 3 & 4 mm Stroke (Made in the USA)
Cordless, coreless, easy to read.
The FK Irons One Update is the redesigned FK ONE—featuring a 1.1″ digital LCD, a brushed coreless motor, and two drop-in batteries that together provide up to 12 hours of tattooing time.
Housing made of 6061-T6 aluminum, manufactured in the USA, with voltage adjustable in fine 0.2-V increments.
You choose your finish— Stealth, Gunmetal, or Pop Pink —and the stroke length: 3 mm or 4 mm.
Built for long sessions that won’t slow you down.
At a Glance
Brand / Model: FK Irons One Update (cordless pen machine)
Finishes: Stealth, Gunmetal, Pop Pink (selectable as a variant)
Stroke: 3 mm or 4 mm, fixed stroke length (selectable as a variant)
Motor: brushed coreless motor—ultra-smooth operation
Display: 1.1″ LCD clearly shows the settings
Battery: two drop-in cells—short (18500A) and long (18650GA)
Run time: short battery up to 5.5 hours, long battery up to 6.5 hours, combined up to ~12 hours
Voltage: 5–12 V, adjustable in 0.2-V increments
Frequency: 80–180 Hz, speed 4,800–10,800 rpm
Grips: compatible with FK ErgoShield grips
Material: 6061-T6 aluminum, Made in the USA
What’s new compared to the FK One
This updated version focuses precisely on the features that matter most in everyday use.
Instead of a simple LED display, you can now read your settings on a 1.1″ LCD screen.
The brushed, core-less motor runs exceptionally quietly and smoothly. Two drop-in batteries—one short and one long—noticeably extend your session time, and you can adjust the voltage in fine 0.2-V increments instead of rough jumps.
Plus, it’s compatible with ErgoShield grips.
3 mm or 4 mm stroke—which one is right for you?
The One Update is available in two versions with fixed stroke lengths.
The shorter 3-mm stroke feels gentler on the skin and really shines when it comes to shading, color gradients, and black-and-gray work.
The longer 4-mm stroke provides more impact and is suitable for bold outlines and heavy packing.
Those who primarily tattoo in one direction should choose accordingly; many artists purchase both stroke lengths for different types of work.
What this means in practice
The wide operating range—80 to 180 Hz and 4,800 to 10,800 RPM at 5 to 12 V—covers lines, shading, and filling in areas.
The 0.2-V increments give you finer control over the stroke, especially when transitioning from lining to whip shading.
The coreless motor ensures smooth, low-vibration operation, which is easy on your hand even after hours of use. And because you’re working with two batteries, you can simply swap them out when one runs low and keep tattooing instead of waiting for it to charge.
FK-One users consistently praise the series’ ease of use and versatility.
The Update version is new on the market and continues this line with the upgrades mentioned—reliable real-world experience specifically with the Update is just beginning to accumulate.
Technical Specifications (apply to all finishes and both stroke lengths)
Finishes: Stealth, Gunmetal, Pop Pink
Travel: 3 mm or 4 mm (fixed, as a variant)
Material: 6061-T6 aluminum
Display: 1.1″ LCD
Batteries: 2 dual drop-in cells (18500A & 18650GA)
Battery capacity: short battery 2,000 mAh, long battery 3,300 mAh
Run time (short battery): up to 5.5 hours (depending on settings)
Battery life (long battery): up to 6.5 hours (depending on settings)
Maximum average runtime: up to 12 hours (depending on battery and settings)
Voltage range: 5–12 V, in 0.2-V increments
Frequency range: 80–180 Hz
Motor: brushed coreless motor
Speed range: 4,800–10,800 rpm
Weight with long battery: 233 g
Weight with short battery: 215 g
Length with long battery: 136 mm
Length with short battery: 127 mm
Maximum width: 38 mm
Compatible with FK ErgoShield Grip
Made in the USA
Package Contents
2 drop-in batteries (short & long)
eFest Slim K2 charger
USB-C cable
Travel case
Category
The One Update is the wireless all-rounder for all techniques.
If you want to adjust the stroke while the machine is running, the FK One Adjust with its wheel-adjustable stroke is the alternative.
If you’re looking for a clearly readable, smooth-running wireless machine with long battery life and precise voltage control, you’ve come to the right place.
FAQ
What colors and stroke lengths are available? Three finishes—Stealth, Gunmetal, and Pop Pink—each with a fixed stroke length of 3 mm or 4 mm. You can select either option in the variant.
3 mm or 4 mm—which should I choose? A shorter 3-mm stroke for smoother shading, gradients, and black-and-gray work; a longer 4-mm stroke for rich outlines and bold filling.
What sets the updated version apart from the original FK One? New features include the 1.1″ LCD, two drop-in batteries with longer runtime, voltage control in 0.2-V increments, the brushed coreless motor, and ErgoShield compatibility.
How long does the battery last? The short batterylasts up to 5.5 hours, the long one up to 6.5 hours; combined, up to about 12 hours—depending on the settings.
Can I adjust the stroke while the device is running? No. The One Update has a fixed stroke length (3 or 4 mm). The FK One Adjust offers an adjustable stroke.
Which grips are compatible, and where is it manufactured? Compatible with FK ErgoShield grips; housing made of 6061-T6 aluminum, manufactured in the USA.
€584.98*
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