What I like galley is ergonomics glasses. They are more easily adjustable. To do this, simply clip on black slats located either side of the glasses then relax at will strap. It is aesthetic and very practical because in this way you can test once the desired length and then reclip. It is also a comfortable product as rubbers adhere perfectly (we forget very quickly this adhesion) and we enjoy a good visual field. This is a purchase that I recommend. Arena is truly a Reference mark.
