A10, I use Monos and dd coils, depending on my site and gold that I have recovered really determines which coil I use.Many times if its trashy with iron I start with a dd and use disc to locate the first nugget in that trashy area. Than I dig everything within the vicinity of the nugget. I clear it all....as I upgrade to medium and even at times my largest a 20" NF mono...just to see if any larger pieces dwell deeper, but most of the times I find the gold to be within 12 inches of the surface. I also have a small sadie mono I use as I get just a bit more depth. But to be honest my most valuable and largest finds were with a dd. If you want the ability to use discrimination and have great target separation you can't go wrong with that Commander coil. Of course adjust you coils to the ground your hunting. Make it a habit to use a variety of coils on those good sites and don't be afraid to experiment with you detector settings. I am not set on all the Commander coils for many reasons and have no brand preference, but I pick the best of all brands. I would also suggest using Detech coils ...in particular the 10x15 Mono..its a KILLER and a WINNER. This coil I would confidently say it has found me the most gold,not in weight ..but shear amount in number. My go to coils are as follows, 10x15 Detech Mono, 10x5 Commander dd, sadie mono NF, and now I am planning to buy the Detech 14 Mono as its waterproof and I hear great things about it. Hope this helps.