High battery capacity: with its 1500mah battery, enjoy 4-6 hours of uninterrupted tattooing. Replaceable rca connector for continuous power.Simple operating system: the built-in led screen displays battery status, timing, and voltage, while convenient buttons allow for easy voltage adjustments.Instant start-up function: it features an automatic start-up function that activates upon powering on, enabling artists to easily work with large rows of needles to meet their diverse tattooing needs.Variable stroke: 2.4 2.7 3.0 3.3 3.6 3.9 4.2 Mm cfor all artists from tattoo to smp.