It fits comfortably on my head and can be worn on the left or right ear. I have no doubt they will hold on my car roof. These ones have better sound quality & get way louder than the JBuds. 0, no es de destacar (me dicen se me oye extraño y yo tampoco lo escucho muy allá). If it holds up, I?d buy it again. I couldnt do more than 20 minutes without taking it off for a rest. A definite do not buy at this price. It seems to be a good product, but i was very unlucky that the attachable microphone button is not working. Both the earbud and case takes 2hrs to charge to full capacity. It really does feel like youre walking on clouds because of the memory foam inside.