Thank you!! They have different profiles. I have a small frame so I was given the high profile so they would project out to the front more and not to the side, so a low profile would have a narrower base so ideal for someone with a bigger rib cage but the surgeon will decide what is best for you! As for tsx I had natrelle soft touch so that is what the s is for and the x for extra high projection. There lots of diff ones like trx is the responsive gel but its basically just the type and profile. Xx