suitable for most metallic and non-metallic materials ultrasonic can go through. transducer models are available for special application,including for coars grain material and high temperature applications. four measurements per second for single point measurement,and ten per second for scan mode. upper and lower limit can be pre-set.it will alarm automatically. Excellent after-sale service for high quality products-two years¡¯ guarantee and all life mainten. Cherry Liu mitech10@mitech-ndt.com