Circuit-Test Solderless Breadboards allow you to easily assemble and test circuits without the use of solder, providing you with a quick and reliable method of prototyping. Available in a variety of sizes, they are an indispensable tool used for student experiments, production engineering and for use in R & D design. Electrical connection is made by inserting your component lead through the hole to spring clips mounted on metal strips within the board. These strips provide a common electrical connection so additional components can easily be added. This series of breadboards has a black anodized aluminum back plate for shielding and multiple binding posts for power distribution.