Exclusky Mountain Bike Helmet, MTB Helmet Adult Lightweight L, Grey\nProduct Details\n--Optimal Ventilation and Lightweight: To ensure that you benefit from optimal ventilation while save physical strength with this mountain bike helmets mens. 18 air vents is formed on this mens and womens mountain bike helmet,while it weights only 280g, extremely comfortable and very lightweight, hardly feel like you're wearing a men's mountain bike helmet. Experience of mountain adventures are quite fatigue-free and comfortable with cool airflow\n--Adjustment System: Single-Hand dial retention system is easy to adjust and secure the exclusky helmet perfect fit on your head, It is very important for you to get cycling helmet on head properly because potential dangers occurs easily with small or big size helmet. please measure your head circumference correctly before purchase, this men's grey bike helmet size is 22.05-24.01 inches/grey mtb helmet 56-61cm(Adult Sizes)\n--Note: Exclusky team fully stant