The FK Irons ONE is engineered for every step of the tattoo artist’s journey. This accessible, wireless tattoo machine opens the door for more artists to create with high-quality equipment at any stage. Premium quality. Sophisticatedly simple. Designed, Engineered & Manufactured in the USA. The FK ONE also arrives with: • High-Quality Travel Case with Custom-Cut Protective Foam • Two Rechargeable Panasonic 18500A Battery Cells • Dual-Battery Charging Dock Product Features: • Wireless Operation with Easily Replaceable, Rechargeable Drop-In Battery - Battery Type: Panasonic NCR 18500A Battery. (Note: We always recommend using high-quality batteries, such as Panasonic) • Quick-Twist Battery Hatch & Power Disconnect • LED Voltage Indicator & Color Spectrum (Note: Blinking light indicates 0.5 Volt increment) • Fixed Machine Body (3.0mm or 4.0mm Stroke) • New Ergonomic Grip - Compatible with all modular FK Grips, including disposable - Click grip needle depth adjustment • Dual-Battery Charging Dock - Charge indicator turns blue once battery is charged. - Use only included power cable to plug in the dock • Compatible with most, standard tattoo needle cartridges How to Operate the Quick-Twist Battery Hatch - Twist clockwise to close & activate the machine’s battery. - Twist counter-clockwise to open battery hatch. - Push down & keep twisting counter-clockwise to deactivate battery. (Note: Cap is shipped in the OFF position)