This LED circuit components is a standard 5mm LED soldered to a small circuit board so it can be snapped into building brick sized blocks. It is designed to connect to other components in a brick based environment using 1/8th inch wide conductive tape.
It can also be sewn into wearable projects conductive thread. It is also compatiable with standard  alligator clips that can be used to connect the LED to other components like the 3v battery holder on a micro:bit or Aduino. The built in resistor provides the needed protection.