I currently have an Explorer SE with a Pro coil on it. It is a good machine and I know it goes deep on silver. My question here is the E-trac that much better? I just brought a used one home from a young fella who said to try it out as long as I want. That seemed like a cool deal. Of course I told him some good agate hunting and arrow head areas! He graduated with my daughter and we know the family well. This E-Trac also has a Sun Ray pinpointer on it. I do not have the owners manual but I do have the Andy Sabich book. Can I tell how old it is by serial number and what would be a fair price on it? Thanks everyone and happy hunting!! Ted