went back to the same school field an found 1quarter 12 dimes 6 nickles an 5 pennies an a old key in 1:45 minute's . i just probe for things that are 4 inches or less in the field because its not my places to digger deep holes. i do hit things 5inches to 9 inches but most of them i just hit onces then i don't hit again . i zap out iron ,zincs pennies an screw tops .