Excellent head protection against crashes and falling objects. Chin strap that wont fall off even when dropped (over 110.2 lbs (50 kg) Inner shell design for ventilation Outer Shell: Polypropylene, Inner Shell: Polystyrene, Head Pad: Soft Nylon; Size: 20.1 - 24.4 inches (51 - 62 cm); Weight: 14.2 oz (420 g) (not including accessories); Certification: EN12492.