... steel) 2,Sound Velocity Range: (1000 ~ 9999) m / s LK300 Ultrasonic Thickness Gauge1. Suitable for measuring metal (such as steel, cast ... ceramic, glass, glass fiber and other any good conductors of ultrasonic thickness.2. Can be equipped with different frequencies, different sizes ... state with prompt functions.6. With EL backlit, convenient in use in dim light.7. With dump energy instruction function, ...