This is a 2.54 mm to 2 mm Female to Female Jumper wire with 20 cm wire length. These Jumper Wires are quite handy for making wire harnesses. It comes in a 'strip of 40 (4 pieces of each of ten colors). The sockets on one end have 0.1" spacing end and fit cleanly next to each other on standard-pitch 0.1" (2.54 mm) header and the other end sockets have 2 mm spacing. They are in a 'ribbon strip' instead of individual wires and can easily be pulled to make a pair of jumpers, or can be kept together to make neatly organized wire harnesses.