|True O scale block signal from MTH. Features include operating timing circuit, when light is changing from Red to Green, it stops on Yellow for 10 seconds, than to Green automatically. baked enamel finish all-metal construction Red, Yellow, and Green LED's. Great detail for the operating layout. Measures 8" high. Operates With Any Infrared Or Standard Track Activation Device Or Relay see www.train-station.com part # PART-SKNP-2C-12AC Operates With Any AC or DC Power Supply Condition: used and boxed.