Review on Giro Syntax MIPS Road Bike Helmet: Enhanced Safety for Adult Riders by Seth Gomez

In general the helmet seems good (only ridden a couple of times). I bought the size medium first as my head size was just under 58cm which is within the max 59cm for M. Well it was too tight especially as I had to wear a headband. I then bought a large one - too big. I had to pull it completely off, and even then it felt wrong. I wanted to return both and look at a different make/model, then checked the M helmet again and found a latch on the back of the helmet. It turns out that it comes from the factory in the tightest setting. After adjusting it to the 'loosest' setting, it now fits both my head and bandage - barely. So I leave the middle one and send the big one back. So be aware that finding the right fit can be a little tricky if you're between sizes.