Sturdiness - incredibly sturdy. Overall:Pros: Price, Quality, Battery, BT, decent bassCons: Smells like cigarette Ash, Hissing noise on ANC and no musicFinal thoughts: If the primary goal is Noise cancelling, maybe these are not the best option. You can still see the charge light through the front and the alignment is perfect for the charger. 5 inch wheel diamondback and my wife and brother have medium size bikes. This 4 th time I had to pair them again they don’t want to pair any more. Excellent bang for the buck. The hooks are bending over and sliding off the cheap plastic holes. The strap is very comfortable. These slippers are very cute, but there are some issues with them1. I wear a 7 1/2 to 8, so I bought a 9.