OK , I got it. Any other tips and tricks or hidden feature about the machine ?

I read somewhere we can change the working frequency of the Q10 detector ( press and hold the ground balance button and use the volume up and down to scroll though) . The question is what's the frequency range we can controll ? On the spec notes it says that it works at about 8 kHz.

Great . I very much appreciate for your answers. Now it is time to search and dig . I'm very exited for my next camp. If I'll find some interesting I'll post some pictures ion here . Franky

OK now I understand. Sorry but I am a newbie here. I have one more question for you. Can you give me more in depth explanation about what C1 to C6 means and how to use them . Thank you very much.

Hello my friend !! I'm not referring to the depth number scale, but when you enter the programming/setting mode and you press the +/- buttons you get some positive/negative numbers on the screen. that's I'm referring to . What they are there for ? You are right the speaker icon is not blanked in the programming mode . What is the meaning ? Anything to do with the volume or what ' ???