Garrett Sea Hunter Mark II Underwater Metal Detector with 2 Search Coils Circuit type: Pulse Induction technology for automatic cancellation of salt/ground mineralization Audio Threshold, Adjustable: adjust to user's preference User-adjustable Discrimination/Elimination Hip Mount Belt/Pouch: reduces detector weight for long searches Discrimination Modes: Two operating modes (Standard or Discrete) offer varying levels of non-ferrous target discrimination.