Update: I was contacted by the manufacturer after my original review. When I buy batteries in a retail setting they are always 10 years out and would have said 2027. The only drawback is they dont stay in your ear for really active workouts like jumping rope. It cleans the occulus lens and removes oil and fingerprints without hurting the lens. My feet are 4” wide. I had some GRUESOME experiences with the cheap cords that came packaged with the Trond BT-DUO transmitter/receivers Im [primarily] using; I didnt know whether these would improve the signal strength enough to get rid of the drop-outs and static I was experiencing . Zur Montage, empfehle ich ein Drehmoment-Schlüssel (6Nm). The charger box light blinks for about 30 seconds and shuts off. Fit great and are breaking in much easier than my last pair - I love them! So I ended up buying a 2XL, and it fit perfect!