I've worn helmets made by Bell, Giro and LAS. Prior to the Trabec Race, I was sporting a Xen. It stayed on, but didn't fit quite right on my head. I had to tighten it down quite a bit on the rocky dh and loosen it up for the uphills to get blood flow.After a year and half of this ride ritual, I decided to use my coupon code and scored one of these babies.
This the best half lid I've ever had. The straps were the easiest to adjust and the retention system did its job. Best of all, it fit like a glove. I didn't have to overtighten it to keep it from jostling around on the rocky descents.
I wear a S in Giro and got a XS-S Trabec Race. So far, can't complain about a thing.