Thank you fir your question. The main difference with the "Extra" line of Mentor implants is a so-called "overfill" of the gel in relation to the envelope of "bag" of the implant, making them less likely to ripple. This is especially tru in very thin patients, or in patients who are undergoing breast reconstruction wherein their implant is literally substituting for their breast. If you consult with a board certified plastic surgeon, he or she can review the different implant types and literally allow you to hold them in your hadn't so that you can judge the difference for yourself. The differences are subtle, and highly unlikely to be detected by you once they are in place after surgery. Best of luck to you.