Thousand Chapter MIPS Adult Bike Helmet with LED Tail Light - Certified Cycling Safety Helmet, Lightweight Low Profile Design for Men & Women, Lockable PopLock System - Perfect for Commuting, Road Cycling & Urban Biking

** INITIAL REVIEW: 2 stars ** (Scroll down to see update.)This helmet is gorgeous and incredibly lightweight, but the advice to size down if you’re on the cusp was 100% wrong for my head shape.My head is 57cm or hat size 7 1/8, and is a “long oval” shape, which means long front to back and narrow side to side. I wear:- a large in women’s hats- a medium in men’s hats- a medium in most bike helmets (Giro, Bell, etc.)- a medium in most motorcycle helmets (Shoei, Arai, etc.)(FWIW, the size medium in the Nutcase Street helmet — a competitor that a lot of people try before shelling out for this Chapter helmet — is too tight on me, and the large is comically big. That helmet just doesn’t work for me at all.)57 cm is on the cusp between small and medium in most helmets, including this one by Thousand. So following their fit advice as well as that of other reviewers — and against my own better judgment — I sized down to a small in this Chapter helmet.Bad move. :( It pinches my head front to back. Awful pressure points; immediately headache-inducing.It’s a beautiful helmet, but I’m annoyed at the misguided advice to size down. Now I need to exchange it for a different size. Will update my review pending a response from Thousand customer service.** UPDATE, two weeks later: 5 stars **Thousand customer service was great. They sent me a medium right from their warehouse in California, and it fits perfectly! Shipping was free. I returned the size small to Amazon.Now that the helmet fits correctly, I’ve explored all the accessories that come in the box.Based on other reviews, I think Thousand has fixed the issue with the magnetic USB tail-light turning on while charging. While I charged mine, only one small LED gently flickered (and then held steady when the charge was full). It certainly wasn’t blinking at full brightness while charging, like reviewers from previous years mentioned.The light does automatically turn on when it magnetically snaps on your helmet. And holy cow is it BRIGHT. I can see how this would be really useful in many cases but annoying in others.I love the pop-lock feature and can easily fit my U-lock through it.I’m convinced that, with MIPS, this is the best helmet on the market. It’s SO pretty and lightweight, it looks cool, it’s super functional, and I love the company’s free replacement policy. I love this helmet!