I was wondering if anyone has used these large butterfly coils.If anyone has they know what I am talking about.I have seen them for the F5 and BH platnium/gold machines.They will work on gold bug and omega also.I figure I would give it a go .I had a 5" coil aftermarket and it ruled-made the mxt very sensative to micro gold and still hit coins at 8".I know the one I had worked as well as they claimed.