The Sewerin M130 valve box locator detects deep and is not sensitive to surface metals, moisture or fluctuations in temperature. The Sewerin M130 reduces false signals caused by objects such as bottle-lids, beverage cans or other small parts of metal. As a result of the downward-directed search field, the M130 can be used in immediate proximity to metal fences or parked cars. The strength of the signal allows reliable detection of the objects sought; even when the M130 is quite rapidly moved.