Thanks Chris. As a new Explorer owner, one of the first things I've done is read Andy Sabisch's Mastering the Minelab Ex. What has caused my confusion in his book, on page 37, last paragraph. I won't read the whole thing. He just mentions the iron mask as a special circuit that it minimizes or eliminates target masking due to a ferrous object. This is what really confuses me. Its important to know , if hunting in preset coins, and would want iron masking as well. But I am with your way of thinking. That iron mask and discrimination are one in the same. If you get a chance, take a look at what Andy wrote and tell me what you think. Thanks for your input Chris, HH Kidd