Sauter tn us ultrasonic thickness gauges sauter tn 230 01us the sauter tn230 01us digital ultrasonic thickness gauge is based on the same operating principles as sonarthe instrument is capable of measuring the thickness of various materials with an accuracy of 01mm and is suitable for a wide range of metallic and non metallic materials sauter tn 230 01us ultrasonic thickness gauge 12 230mm 01mm