Went to my local lake yesterday to try out the MMK with my new 9" concentric coil in the water. The coil stays on the lake bottom and glides through the water with very little to no resistance. I was using Two Tone mode with sensitivity set to 55 and was getting loud strong signals on small pieces of foil. I really wasn't expecting to find any keepers because the water is still too cold for people to swim in. I was wearing my neoprene waders in the water(60F) waist deep when I got a very faint signal. If knew that it was a deep target because there was no ID. After two scoops I finally got it out and it turned out to be a beautiful extremely fine Au750(18K) chain necklace with three charms. It's 17" long and weighs 2.4g. Needless to say, the 9" concentric coil is my coil of choice for this water season!! Thanks for looking.