high precision underground metal detector md-88 outdoor detection of gold, silver and copper coins in the old house

transmission frequency: 6.99 + - 0.2khz audio: 450 + - 10hz power: about 2.5w power supply: 8 1.5v batteries power supply: dc12v accessories: charger, earphone, external battery box, small coil test safety: large coil: 40-45 cm (the size of one coil is 25 cents) small coil: 25-30 cm (the size of a coin is 25 cents) note: the maximum detection depth is tested by burying a 60lx60wx1h aluminum plate in dry soil. generally speaking, the larger the surface area of the detection target, the more detection targets and the deeper the detection depth.