These are wires that have connectors crimped onto one end allowing them to interconnect header pins.  The connector end is female mates with 0.025" square post on pattern of 0.100" centers (male headers).  The wire is solid, so it can be stabbed into a breadboard. These jumpers eliminate the need to solder to the board!  The kit includes 2 black wires and 10 red wires about 12" long.