I have no idea how there are so many good reviews for these. Even though the instructions say to adjust them in your ear until they are comfortable, this clearly shows there's no main way they are supposed to fit apart from jamming them in your ear canal. They also stick out of your ears quite a bit. This in turn means that the weight of them make it even easier to fall out. I would imagine they would be ok if you were sitting perfectly still and not talking while wearing them but while I was eating lunch / talking to some friends they fell out numerous times. Forget working out with them, turn your head a few times / lie horizontally and they fall out in no time.
They do come with 3 different sizes of ear plug but none of them worked for me personally. Sound is good, as is the auto pairing and shutdown but utterly pointless if they fall out doing anything apart from being completely still.