I have a big head (23" helmet size) on the wide side but took a chance with theses not having tried them. The attack were just a little too big. The fit is really good, any narrower and it would touch the side of my face. There is just enough clearance all the way around. The fit is low profile and very comfy. Lenses stay put and are easy to replace once you get the hang of it. I do it slightly differently than the directions and it works so much easier. I like the blue reflex. Very happy. I own the dash xr and fit OK, but sit too low on my nose.