Spark-arc electric and Constant OutputsGreat little addition that adds realism to the back of your wagons or coaches.  Movement turns on the LED and when stationary will automatically turn off after 4 minutes - no power switch needed Fit to brake vans, coaches, wagons etc.Runs for ages on a standard button battery.No pickup, wiring or soldering required as the LED simply plugs straight in The AL23 has two output functions - the FX output flashes a small bright white LED when it detects bumps or rough track simulating the flashes and arcs seen on 3rd rail and overhead electric trains and the ON output is a higher power output for constant lighting inside a coach, brake van or loco cab etc.It is supplied with a small superbright projecting LED for the spark effect and a bright white LED for the constant lighting.  Up to 2 LEDs can be connected to the FX output and 5 LEDs connected to the ON output.