Clear - innovative filter technology blocks 50 Hz Interference ("buzz") that makes tracing difficult Includes Pro3000F50 Tone generator, Filtered 50 Hz Probe, 9V alkaline battery, nylon pouch Precise - SmartTone technology provides five distinct tones for exact pair identification Tone and trace wire on non-active networks Sends loud tone up to 10 miles (16 kilometres) on most cables, loud probe speaker is audible in noisy locations