●Size M: Head circumference 20.5–22.0 inches (52–56 cm) ●Size (L x W x H): Approx. 9.8 x 7.9 x 6.1 inches (250 x 200 x 155 mm) ●Weight: 8.5 oz. (240 g) ●Designed for: Children ●Standard: Safe Goods (SG) standard certified product (for bicycles) ●Specifications: Lightweight soft shell model, size adjustment band