I believe that the different models pertain to size. Some are higher or fatter than others. I am waiting for a GL2006 model that I ordered from Amazon for $26+ with free shipping. It should be here today or tomorrow. Someone else posted using that particular one, so I figured that I couldn't go wrong. I believe that the 2006 is shorter than the stock sight so I may be able to bring my aim up. It seems that everyone that shoots my 9ve tends to shoot a few inches low. Maybe this will bring it up a bit. Better eye sight would also improve my accuracy. I am thinking of buying a special pair of eye glasses just for my serious plinking. I don't need too much pin point accuracy to hit 8" disks at 35ft though. It's those darn paper targets that require better sight alignment.