Using the correct frequency makes a world of difference when locating buried utilities. The depth of the utility, size, material, and amount of congestion (proximity of other utilities) all need to be taken into consideration for the correct frequency selection. Large diameter, direct buried pipes with bell housing ends that use insulators and rubber gaskets, such as water or gas, require a higher frequency, while smaller diameter, well-grounded direct buried or long distance in conduits work better with a lower frequency.

The VM-850 operates at a much lower frequency of 9.82kHz, which is ideal for smaller diameter utilities such as CATV, power, and telephone with less bleeding onto adjacent services.