RANGE 0~ 6000mm (at steel velocity); range selectable in fixed steps or continuously variable. PULSER Spike excitation with low, middle and high choices of the pulse energy. Pulse Repetition Rate: manually adjustable from 10 to 1000 Hz. Pulse width: fixed,nonadjustable Damping: 100Ω, 150Ω,200Ω, 400Ω selectable to meet different resolution and sensitivity need. Probe work mode: Single element, dual element and through transmission; RECEIVER Real-time sampling at 100MHz high speed enough to record the defect information. Rectification: Positive half wave, negative halfwave, full wave, and RF DB Step: 0dB, 0.1 dB, 2dB, 6dB step value as well as auto-gain mode ALARM Alarm with sound and light,.