Id advise ordering at least a size smaller than you normally wear, or possibly even two. You can tell they are staying in more so when you remove the APPs, you actually have to put decent effort into removing the AirPods from you ear, which indicates that they are strong staying in your ear. Not what I expected but they will do and I?m sure I will order more! So I think Birkenstock should generally make toe and ancle straps 1/2 inch longer. I bought this because I have a smaller spool from same brand that came with different sizes. However, I?m always on the lookout for ANYTHING I can wear without them, as I have no desire to wear socks and sneakers, using the inserts, when it feels like 100 degrees like today. The battery seems to last forever . We have a 2018 Jeep Compass that it was supposed to fit. Im sure other people have noted this in their reviews, but in the hopes of preventing more, "Beats by Dre are better than these! Zero issues with:- bluetooth connectivity- charging, I drop the whole case on the charging pads- sound during calls, nobody knows Im using them until I askI appreciate the portability.