NEL Big 15" x 17" DD Coil for Garrett AT Max Series Metal DetectorsThe NEL BIG coil is the deepest coil in the world for different metal detectors, which is confirmed by tests of independent experts in the various forums and searchers at metal detecting meetings! It is recommended to use as a coil for deep searching. The coil is excellent for finding large targets as well as for small targets which are 1g and more at 25 cm depth. Superior to standard coil in depth by 50% and in ground coverage of between 40%.