This is more of an initial review to help people with sizing. Amazon is notorious for leaving out product details, even size info on helmets. Luckily, this helmet has accurate sizing info in the description after you click on each size. The description says Large is 58-60cm, and I believe this is correct. I measured a number of times and got inconsistent numbers, but it was always 58-59 cm (I found this easier than inches, and having a giveaway soft tape measure was very useful, but you could use floss or string and measure it). I was surprised at how inconsistent the helmet sizing charts were on the Internet. Very. In fact, I couldn't even find a proper size chart on Bell's non-motorcycle website. And remember this is a 'youth' helmet, so a normal adult male size is actually rated as a Large here. In fact, my 58-59cm measurement is really on the line between Medium and Large in most size charts, which made it tough for me to decide.I can report that if you measure between 58 and 59cm, you don't want a medium. You want a large. Mine is snug, and the cheek parts are the most snug, and I don't think I have a round head. It's hard to differentiate the tightness of the cheek pieces, which are the tightest, to the rest of the helmet, which to me seems more normal-feeling to me, but not loose. I realize that full-face helmets are going to fit more like motorcycle helmets, and in motorcycle helmet sizing videos I found online, they said they have to fit tighter than many people expect, to the point where some feel like they're too small, but they're not.I don't have any experience with full-face bicycle helmets (and only limited experience with motorcycle helmets), so this is my entry-level effort, yet I don't see what more I'd expect for the price. If you research this helmet, you'll find a review from an outdoor 'gear lab', which gives it low marks. But they're apparently professionals, who then pit this helmet against ones ranging from twice to quintuple the cost, and then say this one feels like a toy because it's so light. It's funny to then read actual user reviews, which are so positive. So in my reading, most criticism focused around comparisons to helmets and features outside its price range, OR confusion in sizing. The most legitimate criticism seemed to be the lack of ASTM-F1952 certification--and I'd be lying if I said I could tell you much about that--but apparently the cheapest helmet on Amazon which has that cert is about twice the price. That's Fox Rampage, which could be a good lead for some readers, and perhaps me someday.My research began with the Bell Super 2R, which begins at twice the price of the Sanction, and the 2R's MIPS version is about 3x, which I was going to get. After losing out on one of Amazon's price fucuations allowed me more research, I saw a number of reports of sizing complications of the MIPS version, then found a number of riders panning it as not a serious answer to a full-face helmet, saying that they could push down on the front of the helmet and it would just pivot and not stay put well, nor did they think it would offer substantial frontal impact protection. Plus, a number of bikers are saying to themselves, if you're going to wear a helmet, why would you want anything less than frontal protection. Some people think they don't need it riding uphill, but under that rationale, do you need any helmet at all riding uphill. So, having worn an open-face helmet in my earlier years, it suddenly made sense to me that I'd never want something less than full-face now. At that point, the advantage of the removable jaw (for my purposes) lost a lot of its appeal.Another thing I didn't like about the MIPS helmets, were that vendors seemed to be releasing a MIPS helmet, and a non-MIPS version together. Now that I know how MIPS works, I don't see any way how this can't create sizing problems. I think a MIPS helmet should be designed as a MIPS helmet from the ground-up, and only be a MIPS helmet, not as an add-on which either takes up extra room, or replaces comfortable padding to try to avoid sizing problems. MIPS seems like it's still pretty new [2015], and I do think I'll probably end up with one, but I think they'll improve. So instead of going crazy with it, I'm starting with this. The Sanction appears to offer more protection than at least a non-MIPS Super 2R, at like half the price. I also like that I could get it in a solid matte black (not a fan of "graphics" am I).I couldn't find any photos of the inside front jaw area. I don't know if the front of other full-face helmets is padded. This one is not, and I know the Super 2R also has no padding in the front either. The Sanction's cheek pads end around my molars. Pushing on the 'mandibles' of the helmet, I find the helmet stays put better when the chin strap is on (duh). I have no problem with the chin strap, but don't know what to expect; it's similar to regular open-face helmets, and seems fine. I'm not sure if the visor is partially to add protection (help keep your face away from the floor), but it seems it could. I have plenty of visibility and probably breatheability and could talk easily with it on, though I do think the helmet is designed more for narrower faces than pumpkinheads. In short, I don't see how the helmet could fit better, having bought it without first wearing it. I tried a number of open-face helmets in a local mart store, and they didn't seem to fit right, and most seemed small, which makes sense because biking is mostly a youth thing, and I guess a medium youth can be different than a medium adult. Some Amazon-sold helmets included literally no actual measurement ranges to guide you through a Large or Medium, so unless you're a gambler, I'd recommend avoiding those. I also found some full-facers cheaper than this on Amazon, actually with good (though fewer) reviews. I went with this one because Bell does a lot of actual research, and that costs money, but produces results. I felt a helmet in this price range was already a bargain enough, and I didn't want to push it further where my head's at stake. Plus enough reviewers gave their specific sizes, I felt comfortable I was buying the right size. If you review, please provide your measurement, the size you got, and how that combo worked!Something I don't like is how the vendors jack around with the prices. When I first shopped, it was seven bucks cheaper than when I went to buy, and now that I've bought, the cheapest price is back down seven bucks, which was close to the price of the 'used' return I bought from Amazon Warehouse. BTW, the Warehouse item was listed as 'like new/packaging may be damaged'. The box was retaped and a little beat-up, but the black fabric (carry?) bag had some obvious dirt on it. I didn't even know it came with a bag though, so whatever, but I wouldn't consider the bag 'packaging'. But, indeed the helmet itself was almost like-new, just some outer fingerprints, which would be expected.Here are a few more newbie observations:- If you wear glasses, you'll apparently have to put them on after donning the helmet.- Good luck if you get an itch inside the helmet. You'll have to take it off to get to it.- I know most open-face helmets' foam is designed to crack to absorb a blow, but I don't see how that would happen here, with the plastic shell. That said, common wisdom says that if you have a crash with a helmet, you should stop using it. I've seen a lot of reviewers talking about continuing to use theirs after a significant impact.- This is probably the best bang-for-buck protection for people upselling from a bottom-feeder/open-faced option.- My cheeks do look a little squished when I look in the mirror, but I guess that's the last line of defense from my face coming out of the helmet.- It's of course heavier than a lightweight open-face, but light for what it is.- Ultimately, this helmet is shaping up to be what I expected it would look and feel like, which is a good thing.