This model was a revolutionary addition to the SX-70 line, introducing the first successful commercial application of ultrasonic autofocus technology in a consumer camera. It is easily identified by the large, gold-mesh ultrasonic transducer (sonar) mounted above the lens, which sends out sound waves to calculate distance and adjust focus in a fraction of a second. It retains the high-quality 4-element 116mm glass lens and SLR viewing system of the original folding SX-70.