Welcome to our shop, we will serve you wholeheartedly! Hope you have a pleasant shopping experience! Hope our products can protect your safety! wish you a happy life!【Bluetooth specifications】 Bluetooth technology: CSR4.1 Bluetooth chip Function: standby for 72 hours, and continuous work for about 12 hours; calls; music; navigation; etc. Features: Strong compatibility; easy to operate; windproof noise reduction. Charging: USB port charging.【Product Specifications】 Style: Bluetooth Motorcycle Full Face Helmet Material: ABS shell+ EPS buffer layer Weight: about 1.6 kg Applicable gender: men, women, unisex Applicable season: all seasons Safety: DOT/ECE Approved Size reference: S=50-53cm,M=54-56cm,L=57-59cm,XL=60-62cmTips: Please leave 1-3 cm as the error range for manual measurement.After-sales service: We promise you 100% satisfactory service. If you have any questions about helmets, please contact us! We will reply you in time within 24 hours! Looking forward to your purchase!