The SRT V270 Battery is Ispire’s slim pen-style battery. The battery is 510 threaded and is a perfect fit for all standard oil cartridges. The battery is button activated and features three voltage settings: 2.9v, 3.3v, and 3.6v.Button Activation with five click on/offChange voltage settings with three clicks of the button270mAh rechargeable batteryMicro USB charging cable includedFits any oil cartridge, but pairs nicely with Ispire’s own Ducore Slim Cartridge