Yundianwei Smart Bluetooth Helmet with Built-in Sensor Light, 3C Certified Electric Motorcycle Summer Safety Helmet for Men and Women, Extra Large Size, Universal Four-Season Half Helmet for Electric

Intelligent light sensing system with automatic high-brightness light switching and dark environment wake-up for enhanced safety

Built-in Bluetooth 5.2 chip with integrated stereo microphones and speakers

Bluetooth functions include music playback, hands-free calling, and navigation voice prompts

Rapid Bluetooth connection within 3 seconds; music playback time 10-15 hours; standby time 48 hours

Semi-enclosed detachable hard impact-resistant ear protectors made from ABS709 material

Large sunroof with 32-hole ventilation system; sliding open/close design for adjustable airflow, operable with one hand

High-impact resistant ABS outer shell combined with high-density EPS cushioning layer for superior protection

IPX4 water resistance rating

Extended windproof visor with quick-release base; flexible, shatter-resistant, and detachable visor

Adjustable head circumference with easy-to-turn knob (clockwise to tighten, counterclockwise to loosen)

Multi-level adjustable buckle with skin-friendly chin pad for comfort and durability

Full size range coverage from S to 5XL (53cm to 70cm head circumference), with detailed internal length and width measurements