These Female/Male 'extension' jumper wires for making wire harnesses or jumpering between headers on PCB's. These premium jumper wires are 3" (75mm) long and come in a 'strip' of 20 (2 pieces of each of ten rainbow colors). They have 0.1" male header contacts on one end and 0.1" female header contacts on the other. They fit cleanly next to each other on standard-pitch 0.1" (2.54mm) header. The best part is they come in a 20-pin ribbon cable. You can always pull the ribbon wires off to make individual jumpers, or keep them together to make neatly organized wire harnesses.