I put the 6"HF DD coil on and what a difference. Tones are solid in 4 tones. My first hunt with it and picked up a very large GM925 mans' silver ring with 38 stones on it. 5" deep. Also got a Hartford Ins Deer pin at 3" and very small. Im a coin and jewlery hunter so I need to get the 10.5 MF DD coil. I have a 11"DD HF eliptical coil on GBSE so no need for another HF coil. Wanted 705 for lower freq. but need DD in my area. Very happy with features and balance and this one is staying in my inventory of MD's.