Instruction: Output yes if the supporting document can answer the given question. Otherwise, output no.

Input:
Question: What is the smallest head circumference this is recommended for? My son is right at 21 inches so trying to decided on youth size or this one.
Document: My son is in first grade but his head measures at the largest size for the youth head gear or the smallest on adult sized head gear. I was worried it would still be a bit too big but it fits perfectly! He even said it was very comfortable and he can't wait for practice.
great head gear, does everything it says it does, it protects the ears and chin perfectly, It also fits perfect, its a adult size but fits a youth perfect also.
This Cliff Keen F5 Tornado 4-Strap Stock Wrestling Head Gear - Royal Blue/Light Gold/Royal Blue is a very nice product. My 8 year old 54 pound son had the Adidas youth AE200 Extero Wrestling Headgear before this one. He always complained about how uncomfortable that one was. He says this Cliff Keen unit is much more comfortable. My son has a smaller head but this Cliff Keen is very adjustable and should last him several years as there is plenty of adjustment left.
The adult size is perfect for my 12 year old son. There's room around the ears, he can hear most of what is going on, and the straps are all adjustable for a NO SLIP fit. I've tried other ear protectors, even from the same company, and this is the best one for no slipping, less sweaty, he can hear, and looks good too.
Purchased this item for my son to use on his high school wrestling team. Very easy to adjust and accommodates larger sizes. He owns this model and the old-school one. This one is lighter in weight. We looked at Asics headgear and found them to be cheaper (at a big box sporting goods store) but could not adjust size nearly as much as the Cliff Keen (old style or new).
My son decided to wrestle this year for his middle school. I was surprised! In the past he has leaned towards other non-contact sports. He has played baseball competitively (on various travel teams) since he was 5. He even tried his hand at rec football (yeah I was surprised by that one too) but he announced that he didn't think he would be pursuing football at his middle school.
I bought this for my 8 going on 9 yr old son. I was a little hesitant at first because it was an adult head gear, buy my son's head measurement were close to the max measurements for youth head gear. This head gear is GREAT! The foam padding around the ear piece prevents opposing wrestlers from getting a grip on the head gear. My son had a wrestler try to grab in a match and he was not able to do so due to the construction of the head gear.
I thought I was getting an adult size but these came and they were a youth size which wasn't in the description anywhere. Sent them back and got an adult size which I love. Awesome headgear (I use for BJJ) just make sure you are getting the size you want.
Once your kid gets up in size/weight/age, like 8th grade 120 lbs, look for one a bit stronger. Until then, this is the best one out there.
This is great heargear for any wrestler. It has velcro on the top straps, so that it can be adjusted for any size head. Very durable.
Answer: yes