For testing bullion http://www.ge-mcs.com/en/ultrasound/portable-flaw-detectors/phasor-series.html As used by GoldMoney... [youtube]http://www.youtube.com/watch?v=rh0Mcagio5Q[/youtube]
Group buy? Guys at Goldstackers use this instead, little bit cheaper at around $350 http://www.omniinstruments.co.uk/products/product/moredetails/omni-tm-8812.id677.html http://www.youtube.com/watch?feature=player_embedded&v=tVjRSye8z-c