4X4, yeah this thing is sweet. You can link it to your pc with a usb cable and then make custom programs from the free software included. You can mix up discrimination, number of tones, ferrous vs conductive, channels, high trash, deep recovery etc... Then even more impressive, you can set the sounds for any area on the grid to specific tones you choose. In other words you could make a penny high, a dime a bit higher and then a quarter squeal as high as a pig, all while setting iron to grunt low. I believe it is something like 50 different sounds you can choose from, which really lets you put specific sounds in specific ranges and keeps you from even having to look at your screen to know what you may have swung over.
now, I will say, as cool as that is, I have already gone back to my favorite settings which is 2 tone ferrous. In iron range, it grunts. Above iron, it squeals. I then use my screen ID along with consistency of signal to decide whether to dig or pass. I like this because I don't discriminate anything out, I want to hear it ALL, all the time, so that the mercury dime below the iron nail still shows up instead of being masked by the iron grunt of the nail. Here are a couple more finds, nothing really special BUT keep in mind, they came from spots I hammered for years with other machines and other detectorists. The silvers screamed and the two silver and nickel spill was 9 inches deep under square nails. Still waiting on a new, virgin site to show up, but as long as I am still pulling silver from old washed up sites, I'm just fine with it!
This thing is basically an e-Trac on steroids, but my years with the etrac are really helping me to shorten the learning curve. I have 30hrs of detecting on it already and am far from even being "comfortable" with it. The etrac took me close to 500hrs until I felt 100% confident in what I was digging and that I was maximizing it's potential. No doubt, if a user hasn't ever used an advanced machine like the etrac, this CTX will take them a long time BUT it will be worth it in the end. Andy Sabisch wrote a book for each of these machines and they were my best investments.