Thank you for your question. The above volume range is that to which a 13.0 cm Moderate Plus saline implant can be filled. However, a breast width of 13.0 cm is probably best augmented with an implant diameter not much greater than 11.0 cm. In addition, the more fluid is inserted into a saline implant, the firmer the implant (and therefore the breast) will feel. Most plastic surgeons agree that you cannot distinguish the difference between a line filled and silicone gel filled implant by appearance, but you can often tell the difference in terms of the feel of the augmented breast. You may have been told during a consultation that the 13.0 cm diameter is best for you, and that may indeed be the case, but it is rare that 13.0 would fit and 13.2 would not. In addition, as one overfills a saline implant, the diameter gets smaller. The best strategy is not to have you, the patient, take on the burden of electing your breast implant. That should be the role of your plastic surgeon based on the input you have given him or her regarding your desired final outcome. That being said, the best way to determine which breast implant size is best for you is by first finding out your specific wishes not only with words or letters as in cup size or “not too big” or “natural”, but also with a visual understanding of what you hope to look like. This can be accomplished either with photographs of patients whose breasts and body type look like you, or ideally with photos of patients not only whose breasts are similar to yours, but are also a similar height, weight, and pre-operative breast size. In our own practice we have provided that unique functionality on our website to accomplish exactly that. Unfortunately the most common reason for a woman to be unhappy after her augmentation is feeling as though she is either too big or not big enough. Thankfully, in our practice this is rarely a problem because implant size selection is what we spend most of our time discussing and determining. I do not place the onus of selecting the breast implant size on my patients since they are coming to me for my advice and expertise, but I do ask my patients to be as specific as possible about their aesthetic goals and I then advise them accordingly. Implants vary in width, projection and volume. This can be very confusing to women, who are used to discussing one number only such as “300 cc’s”. To better understand which implant is best for you, in our consultation room we have two shelves one above the other, each with four implants. The top shelf has all the implants with exactly the same width (12.5 cm), yet the less projecting implant with that width is a 275 cc Moderate or Classic, and the most projecting is a 590 cc Ultra High Profile. On the lower shelf, all of the implants are 300 cc implants, yet the less projecting implant has a width or diameter of 12.8 cm, and the most projecting of the 300 cc implants is the Ultra High Profile which has a 9.7 cm diameter. Once it is determined which implant width or diameter would best fit you, the next step is to decide which what sort of look you are hoping to achieve, i.e. more projection, moderate, or least. This is determined by how much breast tissue you have naturally, and how large you ultimately wish to be. All of this would be discussed during your consultation. And don’t be shy about coming prepared with images which you feel best represent your desired end point. These can be determined by visiting our gallery, or any other photos you wish to bring. The advantage of using our gallery is that all of the relevant information about patient age, implant size and type, are clearly indicated. I would advise you to seek the advice of a board certified plastic surgeon experienced in breast enhancement surgery and make sure that your own sense of aesthetics aligns with that of your plastic surgeon. Your idea of “natural” or “pretty” or “proportionate” might be different from your plastic surgeon’s and it is very important for you to feel confident that you are both of like minds as far as the goals. Best of luck to you and I hope you are successful in achieving the enhancement you are seeking.