Double-Sided. Keep traffic moving safely along your HO streets and highways with this SceneMaster model featuring: Common North American style signals used from the 1960s to 1980s Overall Federal Safety Yellow finish Choose three widely used styles in powered & unpowered versions Fully-assembled from tough metal parts Easy installation in new or existing scenery Long-lasting LEDs Color-coded wiring Operate with Traffic Light Controller (949-4389 sold separately)