I remedied this with a 1/8 ? strip of UHMV on the back of the hooks against the cage. 5 and 12). Shes been wearing them for a few weeks now and very comfortable and sturdy. That being said, I still feel like darth maul when I use this and the songs have their satisfying moments. The sound is amazing, way better than when I put the phone on speaker. not shoe. PROS: Tested on transpacific crossings - over 28 hours of flying in a 787. Also it says Made in Germany. Zapos and Amazon should not be selling knock off Birkenstocks for this price. I ordered a 38M.