I own an f5 machine myself and use the DD coil exclusively, under normal conditions it will go about 8" on Penny's and dimes. Also found that depth readings on targets are really accurate with this coil. I hunt with my two brothers here in WV and lots of times one of us will get a good target reading and call the other ones over to compare stats,my f5 is usually closer on depth than there f75 and omega.Right now my older brother (WV 62)has the ultimate coil sitting at home ready for its 1st run,as soon as this weather breaks we're going to give it a test in the silver den.He tells me that they don't make the ultimate coil for the f5 so that may be an issue.