Let me just say that these are amazing! They were purchased for an outdoor wedding. Also, the clamping force of these headphones are not too tight and wont slip around while on your head. La calidad de construcción es buena. The instructions were mainly diagram based and if you look at each part shown on them (and compare to each part you are about to use - especially the amount and location of screw holes) you can?t go wrong ! ) just a year ago! So I figured I would chance it anyway and get insoles if needed. I ordered based on the size chart and it fits perfectly. However, in these earbuds, I could clearly hear every layer of the music. In short, I LOVE IT!