Those CZ's are amazing. Even with all the modern advancements, they are just about as deep (or deeper) than anything in an open field on coins. They can be a little tougher (for me) on colocated targets…like foil mixed with a coin. I also tend to dig my share of old nails with 'em (although the pinpoint sizing tech can usually tell you it's too big for a coin). I currently have a CZ3D and use it mainly for testing against other detectors for comparison purposed. Brick on a stick sums it up pretty well! However, it will find a TON of old coins...and deep too. Does NASA Tom fix CZ stuff other than 3D's? I don't have a clue what his charge would be though, if he does.