I just got rid of a Prologo Nago Gel Ti saddle. I'm not gonna jump on their website (you can do that and answer the question yourself), but I would venture to say that SIZE and maybe MATERIAL is the big difference; as is the case with most saddle lines from the same manufacturer! Now, as to my experience with Prologo; comfy saddle if it fits you, it didn't fit me so I went for an Antares from Fizik. Do yourself a favor and go to Prologo's website and do a little research!

Mike