I'm giving this four stars, even though I'm returning it. It's really well constructed and it definitely boosts cleavage as promised (see before and after photos) and at $12 it's a bargain. Unfortunately, I'm getting what I call side boob/side fat from where the strap cuts into my back, especially near my armpits (see pics). I personally find that to be really unflattering so I don't keep any bras that do that. I can definitely see this working really well on a leaner torso/physique. For reference, I'm a 36DDD.
Also, I found the top straps to be too short, even at their most extended setting, when adjusted, so the middle part in the back rides up too high (see last pic).

I bought this for an oktoberfest outfilt. Totally works, but you need to put up with a little bit of discomfort to wear it. Especially for long periods of time.

I ordered a size too small. it works very well when i squeezed myself into it but is so uncomfortable because it's too tight on my ribs so I'm unable to use it

Perfect under my dirndl for Oktoberfest. Not comfortable but it's not really supposed to be.

Runs small but really lifts the girls. Is good for back support if your a sloucher. Order one size up from what you think you need.