I just got the 6x10 coil ( f70 coil) and put it on the f75 and hunted and got 8.47 clad and to wheats. I didn't get any rusty caps with the concentric coil like you do with the DD coils and where I was hunt had some trash there and the deepest coin was 8". I dug very little trash 4 things. I have all 4 coil and I like the concentric better the the DD's. 3x7 and 6x10.