Today is my first day with this coil. The weather was too bad for a park search. Did a quick air test with coins, This 21x17 inch coil is sensitive enough with dimes to give a better air test than the 10x12 SEF maybe by 1-2 inches. After running through my coin garden targets got very good to excellent depth on my deep targets. Hit my 11 inch dime with no problem and the deep half dollar. Two of the most popular detectors have a hard time hitting these targets in my soil. HH Ron