[Before Soldering]: Some SMD components are relatively small, be careful not to lose them. The side of the diode with the green dot is the negative electrode. This electronic soldering kit is not a finished product, it need to be soldered by yourself. [SMD/SMT Components Soldering Practice Board]: Input voltage: DC5V. The positive pole is connected to +, and the negative pole is connected to -. After the SMD components are soldered, power on to form a running water lamp to detect the effect of the soldering. [Easy to Assemble]: The connection that was clearly mapped and labeled on the board makes it easy to assemble. And you can refer the marks on PCB board to soldering each component. [Great Soldering Science Project]: This soldering DIY kit help you understand the basics of working with printed circuit boards and become familiar with a variety of electronic components, and practice soldering skills enjoyably and your kids, or students, or DIYers. Precautions for welding:SMD components are relatively small, be careful not to lose., Weight: 0.06393405598 pounds, Manufacturer: rirue