FK Irons LightningBolt Uni Battery — Bluetooth CompatibleTurn your favorite rotary tattoo machine into a cordless powerhouse with the LightningBolt Uni Battery Pack from FK Irons. Uni, converted from the original LightningBolt. Fits all major RCA tattoo machines and brands.The compact yet powerful battery retains all your favorite features from the original design. It is powered by a dynamic USB-C Li-Ion battery and works for up to 10 hours on a single charge, making it extremely reliable for longer tattoos. You can easily adjust the voltage with a quick push of a button.This robust battery also has Bluetooth support, allowing you to connect to the mobile app and access additional features such as voice control, wireless footswitch use, voltage control and eGive.