Start out by checking out
http://www.inamed.com/products/recon/us/patient/tissue/prodinfo.html which has a picture of this implant. You'll see a darker colored circle which is flush with the face of the implant. This is actually a McGhan patented filler valve. The very dark ring is actually a ceramic magnet embedded below the surface of the implant. The slightly darker section in the center of the ceramic magnet is the filler valve itself, which I'm told consists of a hardened stainless steel inverted cone with a leaf spring valve at the bottom. The cone guides the needlepoint to the actual leaf spring valve - the pressure of the needle opens it and the removal of the needle allows the spring to close it. Of course none of this extra "hardware" is detectable in any way since it is all located below the surface of the implant. This is a big plus compared to typical adjustable implants which have a small plastic tube extending from the implant bag, and the valve mechanism at the end of the tube which must be located in the armpit.
The idea is that once these implants are put into the breast pockets, the area with the dark ring is left facing forward (and as you can see will fall in the upper half of the breast). When it comes time for a "fillup", the plastic surgeon merely has to use a compass needle or anything else made of magnetic steel to locate the position of the ceramic ring magnet below the skin. Then he lines up a hypodermic needle attached to some medical tubing and a big bag of saline solution with the center of the location he identified with the compass needle, pushes the needle through the skin and through the outer surface of the implant's valve area, and starts pumping in the saline !
As I said, these adjustable implants are really not intended to be permanent implants, and there is a small chance that the implant's valves can begin to leak saline backwards if used too many times. So the idea is to fill them as much as possible during the initial surgery, then wait until the skin stretches to accomodate the extra breast size, then go back for a fill-up with the doc pumping in as much as possible (like at least 100cc) each time with one needle stick (using like a 1000cc bag of saline, some medical tubing, and a transfusion syringe). Then after each 100cc+ fill-up, it's best to wait another 2 months or so for the breast skin to again stretch and adjust to the new bigger breast size. With the small number of total needle sticks needed using this fill-up method limited to 6 or so there will be very little risk of valve leakage.
A year or so down the road when the implants are filled to 1200cc (or more, depending on how you like the overfilled look - the implants themselves can probably hold 1500cc but will start to look and feel like softballs at that point), it's time to start talking about custom made 1500cc or 2000cc permanent implants to replace the adjustable ones.
The nice thing about using these McGhan adjustable implants is that they're available from stock, and they're also FDA approved for use by any US plastic surgeon in any US hospital or clinic. This means that your girlfriend can have this done close to home the first time. This will be important not only for "peace of mind" knowing that seeing the doc for a checkup is a 10 minute drive away, but also important because she's going to be needing a half dozen trips back to the doctor's office for fill-ups ! When you get to the custom implant stage it will probably be necessary to travel to L.A. and hook up with an experienced doc, but not until then !
I had a set of implants myself once upon a time. I liked the shape a lot, but eventually I wanted bigger ones ! There's a pic of them filled to 1200cc if I remember right ...
Now I have to warn your girlfriend that the experience of having adjustable implants filled is extremely likely to make her a BE addict for life ! During the initial surgery you simply go out under the anesthesia and wake up later with bigger tits. But during the fill-ups it's an entirely different story. You're sitting there fully awake on the doc's office exam table. You see the doc pop the needle into your implant valve which is virtually painless. But as soon as the doc hits the plunger of the syringe and starts pumping saline, you can see and FEEL your boobs becoming pressurized - then stretching, then Growing heavier and Heavier and HEAVIER - thrusting forward more and More and MORE ...
