He walks a ridiculous amount of miles each day. They dont come off but they do get loose,,which makes me afraid to cut the string after I tie them on. The PX7 allows for USB DAC functionality as well as normal Bluetooth operation while charging which is something the Bose, Jabra?s and Sony?s cannot do. I bought these thinking they would be the same as the Tevas I loved and lived in when I lived in Colorado. At full charge, which can take up to 5 hrs, you can listen to music for 20 hours at 50% volume. im so disappointed. I like this hat. These were the SIXTH attempt at shoes and SUCCESS! Autoconnects when I get near my car, and runs while charging. I screwed this in by hand, it was a bit difficult, but did not take too long and is very secure.