Caught with a dead battery, there are no spare parts even on Ali. I do not advise taking it, it is better to pay a little more and take a full-fledged brand. Disassembling the device is simple: first, we pull out the buttons, they can be removed without problems, then there is a plastic plug at the bottom of the device, it can be pry off with a sharp object, such as a scalpel, it is removed, then the whole mechanism falls out by itself from the side of the laser, the battery is called ATuMan 651720 (3, 7 V, 0.82 Wh, two-pin with control board), unfortunately they are not available for sale. I came across a defective one, there's nothing you can do, it's good that it's inexpensive.