Based on the particular make & model detector and for the search site and conditions. Some detectors only have DD coils in the size-range I want, and some detectors do not have any Concentric coils available. But you are correct, as a rule I favor a Concentric coil most of the time.

With my F75+, I am fine with the 3.5X6.5 Concentric for most applications I have for it when Coin & Jewelry Hunting. I am sorting through all of my extra coils and detectors that I am going to thin-out and have 3 coils that work on an F75 or an F70 / Patriot. Those are:

* A Brand New 5" DD I just bought

* A Brand New 5.5X9.75 Concentric I just bought

* An 'as-new' MGC (MaGiC) 5X8 Double-D

Since I already have an 'OOR' DD on a Racer and a CoRe, and a 5" DD on a Relic, I'll likely let the new Fisher 5" go. Thinking about the almost 10" elliptical Concentric, but I might just keep only 1 extra coil for the F75+ and likely a mid-size. Either the MGC, that functions more stabile than Fisher's coils, or I might try a NEL Sharpshooter DD open-frame coil.

Moving to Utah is getting close and I need to clear out some detectors and coils. Have you selected anything new-to-you yet?

Just before I ended up with bad pneumonia and in a diabetic coma that had me down for a month-and-a-half, I received a few detectors that I never used outside. One is the really versatile Nokta Impact w/7X11 DD standard coil. And I bought a new 5" DD and new 7" Concentric. In my opinion those are the two best coils for it for urban locations as well as most Relic Hunting locations. Plus I found the Impact to balance better and work better, all around, than the Racer II I had at the time.

Monte

"Your EYES ... the only 100% accurate form of Discrimination!"
Stinkwater Wells Trading Post
Metal Detector Evaluations and Product ReviewsI'm now 'back home' in Farr West Utah monte@ahrps.org ... or ... monte@stinkwaterwells.com 503-481-8147Detector Outfit: A selection of my chosen makes and models, with the best coils mounted for the tasks I'll take on.F-19 .. Racer .. Vanquish 540 .. FORS Relic .. Silver Sabre µMAX .. Bandido II µMAX .. XLTPinpointers: Garrett AT Pro-Pointers .. Headphones: 'Hornet' .. MS-3 Z-Lynk .. ML-80 *** All working well today to make memories for tomorrow. ***