기능

• It is a product from the vacuum tube era that old fans miss, but it is still in use. Before the widespread use of printed circuit boards, it was a typical style to assemble resistors and condensers in an orderly manner, draw out cladding wires, and connect them to vacuum tube sockets. Even in the age of transistors, it has been used to construct experimental circuits for beginners because of its large structure and easy soldering.