The battery is a rechargable lithium ion coin cell battery and it is charged from a micro USB connector. The battery life depends on how heavily the pocket watch is used, but if you leave it alone, it is estimated to last several months. There is a low battery indication feature. This pocket watch also feature a buzzer and a vibration motor, which are used for the alarm feature, and the motor causes a short "tick" as each second passes by. The pocket watch is constructed of a PCB, two pieces of laser cut clear acrylic plastic, and a 3D printed casing.
All the files are also available from my Github (there is a single ZIP download option on that page). This will include the microcontroller source code, circuit schematic, PCB layout, laser cutting vector file, and 3D models. Everything is open source, and also ready to be sent out for fabrication.