Universal circuit board with several LEDs, which will fit in most of the passenger cars in the Märklin H0 program. One 73400 is required for a short car (example: Langenschwalbach cars), for long cars (example: UIC-x at 28.2 cm / 11-1/8" length) two 73400 are required. The circuit boards can be plugged together in a series or they can be shortened. Mounting hardware is included. The separate 73404, 73405 or 73406 pickup shoe / ground spring power feed set, or the 72020 current-conducting coupler with the 72050 ground spring is required, depending on the car type.