Why one detector just seems to be "hotter" then another of the same model is but a guess, at least on my part, but we know that is sometimes the case. Elton has two 6.5 versions and one seems to be "hotter" then the other. Both 6.5 versions. Consequently, there simply might not be a difference between the 6.0 and 6.5 versions, just, for whatever reasons, the occasional one detector is or just appears to be "hotter" then another. From one day to the next, my Omega and F 75 LTD on occasion seem to light up targets better then they did the previous day. And, there are reasons why this sometimes does occur. Just my thoughts, anyway. HH jim tn