Battery Type: 2000mAh Lithium Battery (Included). Adjust Stroke Length: tattoo machine pen built in 2 steel ball, make a crisp sound when adjusting, rotate the handle to adjust the needle stroke in 2.3mm, 2.7mm, 3.2mm, 3.8mm, 4.2mm, 4.5mm, will not change the needle stroke during the tattoo process.
eBay