The bulbs on these light strings are constructed in 3 circuits that turn on and off sequentially - one, two, three - at a rate you chose with a controller box. Used in a straight line, the alternating lights will look like they are "traveling". Randomly bunched together on a shrub or in a container,they'll appear to randomly twinkle on and off.
These string lights have one stackable male plug only. Up to 2 sets can be stacked together at one plug. These chasing Christmas light sets are approximately 46 feet long with 4-inch bulb spacing.