I agree with what Parkit and Khouse said inasmuch as square tabs can fool you a little and after you dig a couple hundred you might forget about digging those nickle signals. But, if you realy listen, there is a difference in the tone between nickles and square tabs. The nickles seem to have a deeper, more solid tone and the square tabs more of a higher tone. When I'm hunting, when I get a signal that locks in on a nickle, I'll say to myself, "Nickle" or "Squaretab" and then dig it up and make a mental note of what I heard. This seems to get me more nickles, maybe just because I'm playing a game and not getting disgusted at all the square tabs, but I really think it helps me hear the difference. Another thing is there just aren't as many nickles in circulation as other coins. As a check, save your pocket change for a week or two or however long it takes to get about a cup full. Then look at the ratio of nickles to other coins. I figure it's the same way in the field, just not that many compared to other coins. I have attached a photo of the loot I got this weekend on a hunt using my Nickle Game. I got 10 of 'em and 8 Mexican coins that hit in the nickle range as well.