Howard, don't do like a guy in my club did. The first few weeks he had his CTX, only dug targets that registered on the 12FE line. He asked me at a meeting if that's where ALL the good targets read. The answer of course is no. I always allow a tolerance (plus or minus) on my numbers, more-so on the FE number reading than the CO. A lot of things can cause the target not to read exactly on the 12 line. After you dig a few targets, the "picture" will become much more clear as to what is more than likely a good target........If you watch any of the videos of the CTX, providing they show the numbers before the dig, try to guess what the target is based on their numbers before they recover the target. You can, also, scan coins to get a good idea of their FE/CO numbers, but these numbers can vary somewhat when a target is in the ground, due to co-located targets, mineralization, coin at angle in the ground, etc...........Good Luck...HH