Wow thanks for the education....so mine are in a horizontal orientation. Same with the one that I busted that I'm trying to replace. I guess that web site mislabeled one with no flutes as "optic lens", seems like they got it backwards. What sort of effect would I experience with a checkerboard or non-optic lens, as compared with what I'm used to with the horizontal-fluted lens?
Obviously for an interior application like this Flatlighter, I'm trying to minimize interior light scatter and reflection inside the vehicle. On the other hand, light that goes out the windshield and 90 degrees off center to both sides is a good thing. Should I try something other than the horizontal fluted lens for the second lens, that might complement the capabilities of the horizontal one?