Handy for making wire harnesses or jumpering between headers on PCB's. These premium jumper wires are a little over 30cm long and come in a 'strip' of 40 (4 pieces of each of ten colors). They have 0.1" sockets on either end and fit cleanly next to each other on standard-pitch 0.1" (2.54mm) header. We recently updated these so they are in a 'ribbon strip' instead of individual wires. You can always pull the ribbon wires off to make individual jumpers, or keep them together to make neatly organized wire harnesses.