I am a trans ftm teen with a good sized C cup chest. These binders don't completely flatten my chest (as most trans individuals will find with most binders, especially the larger the chest) but do give me more realistic man pecs. They are comfortable and pretty breathable, but I wear body powder when its hot to help with the sweat. I have tried some other binders, but these are my favorite and I have bought this pack several times. Would, and have, recommend to a friend.