This 15 inch DD coil gives a huge depth advantage over the 11 inch, especially when used with the boost or cache modes. The depth is incredible, punching down to the deep virgin ground that is out of reach for all other detectors. The DoubleD configuration and speed of the Fisher still gives excellent separation for a coil this size. For use with the Fisher F70, F75, F75+ and F75LTD metal detectors.