I checked these were fully charged and replaced them in the headset and hey presto - I was in business. Husband usually wears 10-1/2 shoe so he ordered size 11, but they were too big. De hecho a veces las resalta, pues al atenuar por ejemplo el ruido del tren, se oyen hasta más nítidas las voces, aunque no me molestan. My 3 1/2 year old LOVES these shoes! Sound quality is far beyond expected! I am high waisted, however. I already have a perfectly excellent pair of Bose over-ear bluetooth headphones, so didnt really need these, but since they were effectively free, I decided to go for them. He tried on this style in person in our local Birk store for sizing purposes, then saved $ by purchasing them here! The adjustment slots (maybe 20) give you a lot of flexibility but as I said, the 16" bike is the smallest this will go on. This one is wrap one (large) pull 2 and pull 3 and you are done.