This heat pen uses AA batteries. It has been tested and is in working order, so you can buy with confidence. It heats up in about 1 second after turning on, making it very easy to use. It provides a cleaner finish than using a lighter to melt the thread ends. You can work close to the edge, so you can leave the thread shorter than with a lighter (Image 3). If you try to melt the thread without cutting it first, the finish will be worse. I also use this product myself, so please feel free to ask if you have any questions. I use rechargeable batteries with it. In addition to leathercraft, it can also be used for various other purposes such as processing 3D printed products, plastic models, wood burning, and lost wax casting for jewelry. * Batteries have been inserted to check operation. * The package has been opened once, so it is not included. ¥200 off when bundled with other items. (Please request in the comment section or using the bulk purchase function before purchasing.)