The Gold Bug Pro Combo is outfitted with a small 5" DD coil as well as a 10" DD coil. The 5" coil is best-suited to finding gold nuggets. Small search coils, intended for gold prospecting, are designed for precision. The Gold Bug Pro’s small DD search coil makes pinpointing easier, fits into small spaces where gold is often hidden, is better suited to penetrate highly mineralized soils where gold is frequently found, and has the highest possible sensitivity to tiny gold nuggets. The larger 10" DD coil is excellent for Relic Hunting by being able to cover more ground and give better depth to find the treasure buried further underground.