Panther X, originally created for 20 time World Champion, has been considered the top shooting glass in the world since it's introduction in 2003. Snap Tech lens changing system, zero visual interuption, total adjustability in the frame are just a few of the things that make this model a choice of champions. The difference between a post and a no post model is in the nose piece. A Post model has vertical adjusment and is capable of accepting a prescriptive insert. The no post model is a plano only version and has perfect site registration with zero visual interruptions.