Velleman MK131 Traffic Light
Stop. Look. Solder.   Suitable for model towns, railroads, and teaching the basics of electronics and soldering. This high-quality traffic light kit needs only your soldering iron, a 9V battery and a steady hand to yield a 4-1/2" tall, 4-way stoplight with red, yellow and green LEDs (which cycle automatically at an adjustable rate) on each face.