This has to be one of the worst pair of earphones I have ever used... The ear clips failed to do their basic job of keeping the earphones in, whichever size I used. Even worse is the sound quality - the earbuds -again, whichever size you used - failed to do a decent job of keeping the earphones in. They failed to isolate any outside sounds, resulting in a) leaking of sound to annoy anyone around me and b) seriously tinny sound quality. Because of the shape of the earbuds, you cannot replace them with other, better fitting types either.
I cannot comment on how long they last on a single charge, as I could not use them after trying them for the first time; they just sounded so bad.
For this price - scratch that, for half the price, you can get MUCH better.