This is a very affordable Pulse Induction detector that can be used underwater to 60 metres. 

• Circuit type: For automatic cancellation of salt/ground mineralisation this uses Pulse Induction technology
• Audio Threshold, Adjustable: user adjusts to suit preference
• User-adjustable Discrimination/Elimination
• Hip Mount Belt/Pouch: eases detector weight to enable long periods of searching
• Discrimination Modes: Two operating modes (Standard or Discrete) offer varying levels of non-ferrous target discrimination.
  • Discrete Trash Elimination: use to eliminate most pull tabs and foil without significantly degrading sensitivity for rings and coins.
  • Standard Trash Elimination: provides the deepest possible detection; allows a very slow searchcoil sweep in areas with little trash.
• Battery compartment independently sealed
• Search Mode: Non-Motion All Metal Deep Seeking Mode with
  Full Range PI discrimination