Universal circuit board with several white LEDs to fit in most of the passenger cars in the Märklin H0 program. One 73401 board is required for a short car (example: Langenschwalbach cars), two boards are required for long cars (example: UIC-x cars with a length of 28.2 cm / 11-1/8" length). Several of these circuit boards can be plugged together or a board can be shortened. Mounting hardware is included. Depending on the car type, the separate pickup shoe / ground spring set, item nos. 73404, 73405 or 73406 or the 72020 current conducting couplers with the 72050 ground spring is required for electrical connections.