Keep a familiar pen in hand as the tattoo moves from lines to broader colour. Thunderlord Power U9 gives you seven selectable stroke settings from 2.0 to 4.2 mm, a universal cartridge connection and interchangeable battery power. Choose it when changing the mechanical response belongs in your tattoo routine; start with two batteries if a prepared spare is part of the setup. Seven settings: 2.0, 2.4, 2.8, 3.2, 3.6, 4.0 and 4.2 mm. Standard universal cartridge connection. Battery indicator and usage timer. One- or two-battery packages. Choose your U9 working package Adjust the pen response without changing the whole setup The seven stroke positions let you compare the mechanical response you prefer within one pen. Keep the cartridge, design task and hand movement familiar while assessing a setting, then choose the response that belongs in your established technique. The adjustment earns its place when your work moves between different marks rather than staying with one fixed routine. A fixed-stroke machine is the simpler choice when you want one familiar mechanical setting. Choose U9 when the range of adjustment itself is useful, with the battery indicator and usage timer keeping key information visible.Choose one battery or keep a spare ready Choose two batteries for a routine built around rotation. Prepare the spare before work and exchange packs between sessions as needed. Choose one battery for a more compact package when that supply fits your existing charging routine. Both package choices keep the same black U9 pen and its seven stroke settings. Make the power choice around the station’s preparation schedule, then choose the cartridge configuration for the design.Give each tattoo section the working tip it needs The universal connection supports compatible standard cartridges. Choose Thunder Pro RL for contours, RS for compact local colour, M1 for broad directional fills and RM for softer-edged gradients. For finer grouped linework, start with 0803RL or 0805RL; for a smaller gradient, compare 1005RM and 1007RM. The cartridge gives each section its working geometry, while the machine adjustment lets you develop the response alongside it. Built to the highest professional quality standard, U9 combines adjustable stroke and interchangeable power in a tattoo pen designed around a varied working setup.Choose the two-battery package when a ready spare supports your routine, then select the cartridge family around the first mark you plan to make. How should I compare stroke settings?Use a familiar design and cartridge on a practice surface, change the setting you want to assess and compare the working response with the rest of the setup kept consistent. Choose within your trained technique.Can I use my universal cartridges?U9 uses the standard universal cartridge connection. Use compatible cartridges and choose their arrangement, count and diameter for the design task.Back to battery package selection