FK Irons ONE Adjust – Adjustable Stroke Rotary Tattoo Machine - 2.0mm–5.0mm

Built to Adapt, Engineered to Perform

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

All-Day Wireless Performance

Enjoy nonstop, all-day wireless performance with 2 swap-and-go rechargeable Panasonic batteries. Each FK One Adjust comes with one large battery (18650A) for up to 6.5 hours of power, and one small battery (18500A) for up to 5.5 hours depending on your settings. A dual-slot charger is included so you always have a battery powering up and ready to go.

Full Visibility & Control

The FK One Adjust features an upgraded digital display giving you a crisp readout of your operating voltage or hertz—your choice. Hertz offer a more accurate measurement of your machine’s performance, showing the exact frequency of needle movements per second for precise, real-time control.

Artist-First Design. FK Standard.

Built with direct artist input, the FK One Adjust is designed to handle everything you throw at it day after day, session after session—from first line to final pass. Reliable, durable, and built to last, backed by FK’s global service program.

How the Stroke Adjustment Works

The FK One Adjust features an innovative custom engine that redefines adaptability. A fixed-stroke cam connects to a precision paddle, while a rotating slider adjusts stroke length by moving closer to or farther from the paddle’s center. This design reduces friction and wear, keeping performance consistent session after session.

A first-of-its-kind system built to keep your flow uninterrupted and your performance unmatched.

Technical Specifications

• Machine Size: 152mm x 38mm
• Weight: 244g (8.6oz) with 18500A battery / 268g (9.5oz) with 18650A battery
• Stroke Range: 2.0mm–5.0mm (patent-pending adjustable, no power-down required)
• Operating Range: 5V–12V (80Hz–180Hz)
• Voltage Adjustment: 0.2V or 0.5V increments
• Maximum Output Current: 1A
• Motor: Brushed motor
• Display: Upgraded digital screen – volts or hertz readout
• Grip: Ergonomic grip included; compatible with FK Irons modular grips

Battery Specifications

• Includes 2 drop-in rechargeable Panasonic batteries + 2 caps + dual-slot charger
• 18500A Battery: ~5.5 hours | shorter cap (0.25" depth)
• 18650A Battery: ~6.5 hours | longer cap (0.75" depth)