After 30 minutes, THIS adapter only charged 12%. It also Pauses and Plays your music. Maybe I will return it, or throw it to the trash can. the battery life had to be the worst they Promise 10 hours, youre lucky to get 7. IT almost makes me want to replace all my other kickstands with these. I was skeptical about these Xelastec ear tips but they work well for me. Purchased with the regular outlet plug in device which makes it easy to charge anywhere, if you do not have a USB port. These hooks were easy to install but I used shorter screws than the ones that were provided, which were apparently meant to mount these hooks on a wall and were so long that they would have gone all the way through our door. The 4 was a stereo unit, this is mono and they no longer stay on when plugged in. This is my second pair of Birks.