Built to Adapt, Engineered to Perform 

Enjoy versatility with no limitations when you tattoo with the FK One Adjust. The FK One Adjust is built to adapt to any style, so you can pursue any project for any client. This patent-pending stroke adjustment technology delivers effortless adaptability, so you can tackle any technique on the fly. Easily adjust your stroke mid-session without ever having to power off your machine. One setup handles everything: no need for swapping machines or cams mid-session. 

Enjoy nonstop, all-day wireless performance with 2 swap-and-go rechargeable batteries. Each FK One Adjust comes with one large battery for up to 6.5 hours of power, and one small battery for up to 5.5 hours (depending on your settings and operating parameters). This machine also gives you a dual-slot charger, so you can always have a battery powering up and ready to go when you need it. 

Get full visibility and control over your performance. The FK One Adjust features an upgraded digital display that gives you a crisp readout of your operating voltage or hertz according to your preference. Why Hertz? Hertz offer a more accurate measurement of your machine’s performance, showing the exact frequency of needle movements per second.  

Trust in the FK standard, knowing the FK One Adjust has an artist-first design. This machine was built with artist input and is specifically designed to handle everything you throw at it day after day, session after session, from first line to final pass. It’s reliable, durable, and built to last, supported by FK’s global service program. 

Technical Specifications: 

• Machine Size: 152mm x 38mm
• Weight with Battery: 244g (8.6oz) w/ 18500A Battery / 268g (9.5oz) w/ 18650A Battery
• Features patent-pending adjustable stroke technology (adjust your stroke without powering down)
• Upgraded digital display screen: shows power output in volts or hertz according to your preference
• Stroke Range: 2.0mm up to 5.0mm
• Equipped with an ergonomic grip for maximum comfort
• Compatible with other FK Irons modular grips
• Features a brushed motor
• Output Voltage: 5V–12V
• Increment/Decrement Voltage Interval: 0.5V or 0.2V
• Maximum Output Current: 1A 

Battery Specifications:

• Comes with two drop-in, rechargeable Panasonic batteries + 2 caps
• 18500A Battery Life: ~5.5 Hours (dependent on settings + operating parameters)
• 18650 Battery Life: ~6.5 Hours (dependent on settings + operating parameters)
• 18500A Battery uses shorter cap → 0.25” depth
• 18650A Battery uses longer cap → 0.75" depth 

User Manual