HJC has created a true youth, off-road helmet with the CL-XY II. The youth-size polycarbonate shell provides a lightweight helmet, with superior fit and comfort using advanced CAD technology. The "ACS" Advanced Channeling Ventilation system allows full front to back airflow to flush heat and humidity up and out. A large eye port provides maximum visibility and superior goggle fit. Available in four youth sizes (S, M, L and XL). STANDARD DOT: Meets or exceeds DOT FMVSS 218 approved. Testing includes energy attenuation, penetration resistance, chin strap structural integrity, and labeling requirements for on-road motorcycle helmets Advanced Polycarbonate shell: Lightweight, Superior fit and comfort using advanced CAD technology. Large Eye Port: For maximum visibility and superiorgoggle fit. "ACS" Advanced Channeling Ventilation System: Full frontto back airflow flushes heat and humidity up and out. Plush, NylexA(R) Interior: The warranty is applicable to manufacturers&'; defects for up to 3 years from the date of purchase or 5 years from the date of manufacturing (whichever comes first). YOUTH HELMETS Size Head Circumference Hat Size Small 19.29 - 19.69in (49 - 50cm) 6-1/8 - 6-1/4 Medium 20.1 - 20.5in (51 - 52cm) 6-3/8 - 6-1/2 Large 20.9 - 21.3in (53 - 54cm) 6-5/8 - 6-3/4 X-Large 21.65 - 22.05in (55 - 56cm) 6-7/8 - 7