Anyone use these coils? I Want to get one for gold prospecting creeks and Water poof is a must. I was looking at the 5 inch point, or the 6.5 by 3.5 DD coil. Is there something special with these, or is the minelab 6 inch coil just as good? I also got one more question dose coiltek make a small DD or higher feq coil for xterra, not the big coil. Thanks