These jumper wires consist of Multiple jumpers that can be connected next to one another on a 2.54mm female header. Comes in one pack of 40 jumpers (colors as shown) each is 20cm in length. These jumper wires can be used for pretty much everything! They work great with breadboards, Arduinos, and really any 0.1″ pitch prototyping board also Fits into 2.54mm female header.