... 4,8,16 Operation mode Single probe transmitter and receiver, dual probe transmitter and receiverScan mode A,B,C ... range(steel longitudinal wave) 0~6000mm Frequency range 0.5~20MHz Repetition frequency 100Hz~10KHz adjustable Vertical linearity ≤3 ... CLOCKEncoder50-1024 (Optional)Detector modepositive, negative, bi-directional, radio frequency (RF)Peak memoryCan choose echo peak memory display,background ...