Features patented Target Identification System (TID) Locates valves and curbs up to 9 ft. deep, survey markers up to 8 ft. deep, and PK nails up to 14 in. deep Provides unbeatable performance locating targets near a fence line Excellent for finding buried ferrous objects including PK nails, iron pipes, valve covers, masonry nails and old hidden culverts The Fisher Labs FPID2100 Ferro-Magnetic Locator features a patented (TID) Target Identification System designed to save time from digging unnecessary holes, especially in hard or frozen ground. This unit can effectively locate valves and curbs up to 9 ft. deep, survey markers up to 8 ft. deep, and PK nails up to 14 in. deep. The FPID2100 pinpoints to 1 in. of center for valves and curb boxes. The strong ABS plastic housing offers protection in the field.