Practical Soldering Project Kit - This solder practice project will help you achieve good soldering techniques, help you become familiar with a variety of electronic components, and provide you with a completed unit that will produce the fun sound of the two tone European siren. This kit is an example of a multivibrator circuit. Working with printed circuit boards is in the future of every electronic technician. Almost every electronic device today has a printed circuit board and whether you are assembling a PC board or repairing it, you must understand the basics of working with these boards. Requires one 9V Battery. Made in the United States