Rotors are sprinklers that shoot a jet of water. The stream is moved back and forth across the area to be watered. Over a period of time, the water distribution is uniform. Rotors usually have a relatively low precipitation rate, so one station of rotors can cover a large area. There are single stream rotors, multi-stream rotors, full circle and part-circle arc rotors. The best rotors are gear driven rotors. Avoid impact rotors because the open cases cause big reliability problems.