My VLF detectors are rapidly sorting themselves out and I am satisfied I am doing about as good in that regard as can be done. There really is only one area of metal detecting left that is bugging me. 2019 Update: The Manta is now called the Fisher Impulse AQ - see Fisher Impulse AQ Detector Data & User Reviews The Garrett Infinium was the first waterproof ground balancing PI and not a bad first effort. White's TDI might have improved on it but White's never did a waterproof TDI. S