Polymer guns are just plastic formulas, right? And presumably they add some sort of coloring agent to make them black or brown or green or whatever. How about this-say that Glock decided to leave their plastic frame compound transparent and make some frames and magazine bodies from clear polymer compounds with no additives. Then you would have a really unique gun, one that lets you see inside the guts and also, since the mag body is clear, you would have sort of a "cartridge counter" feature, you could just look at your gun to check your magazine reserve? Crazy idea or what? They make clear plastic mags for the Ruger .22's so you can see inside to count your reserve. Except the gun itself does not let you see thru it. Also the clear banana mags for the Rugers let you check your loads. Lugers once had a window in the grips to see into the mag with a slot down the side. Rare variation.