The helmet is just right for her, and it was easy to adjust the chin straps. His head is 21 inches in circumference and this fits him well. The chin straps are adjustable.

Not sure how to contact outdoormaster about my dissatisfaction of their product. It's in defective condition when arrival.

It keeps slipping off his head and creates a safety gap. While you can technically put it back in, it never stays. External material seems to be plastic paper!

The tightening band that keeps the helmet secure on the skull is removable and only held on by velcro. The crown/head sizing piece is not connected to the actual helmet. The velcro attaching internal padding of helmet is also poorly made.