Specifications:Dynamics design can reduce resistance and increase air intake to accelerate air flow, while effectively reducing the temperature in the helmet and keeping it cool.Ultralight design create a perfect bike riding experience.Equipped with high brightness taillight, ensure a safety night cycling.The head circumference is adjustable.Sunshade helmet brim has the function of sun protection.Type: Bike HelmetMaterial: EPS + PCTaillight Battery: 1 x CR2032 Battery (Included)Features: Sun Protection, Ultralight, with Taillight, Safe Cycling, Adjustable BandSize: 17cm x 21cm/6.69" x 8.27" (Approx.)Head Circumference: 57cm - 62cm/22.44" - 24.41" (Approx.)Notes:Due to the light and screen setting difference, the item's color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Bike Helmet
