Many industrial steel detectors are well balanced coil methods. A few coils are wound onto a non-metallic frame and each coil is precisely parallel with one other two. It may possibly work on all types of metals (iron or non-iron) and can detect larger sized steel objects around 3 ft. https://jaspervkxky.goabroadblog.com/28520157/the-best-side-of-metaldetector