A visual indicator was developed based on vibrating reeds, which provided a simple panel-mounted "turn left-right" indicator. It was reliable, easy to use and more immune to erroneous signals than the competing audio based system. Pilots who had flown with both aural and visual systems strongly preferred the visual type, according to a published report.[1][16] The reed-based solution was passed over by the U.S. government, however, and the audio signals became standard for decades to come.[7][3]