A breadboard is a reusable solderless device used to build a (generally temporary) prototype of an electronic circuit and for experimenting with circuit designs. This is in contrast to stripboard (veroboard) and similar prototyping PCBs which are used to build more permanent prototypes or one offs and cannot easily be reused. Usually breadboards have strips (known as bus strips) down one or both sides either as part of the main unit or as separate blocks clipped on to carry the power rails. Sometimes there is a sticky foam backing and this will often cover the back of the entire assembly as sold even though the breadboard itself is in several parts.