SIZE:This adult cycling helmet goes with perfect size, Head circumference 57-62cm, head width 7inch/18cm, head length 9inch/23cm equipped with the easy-use dial system and side straps make this nutcase helmet adjustable to different head size and suitable for both men and women. VENTILATION:The bike helmet designed with18Air Ventsensuring optimal air flow.The adoption of specialized aerodynamic and ventilation design allow air go through the biking helmet which help increase the speed and keep stay cool. SAFETY: We follow 3 crucial steps to achieve a solid constructed bicycle helmet by first placing the exterior shell in the mould, then reinforcing it with a skeleton and finally adding the foam that will hold all the parts firmly connected, thus making sure you are safe in a case of an accident. COMFORTABLE & VENTILATION:The inner pads provide comfortable wearing experience,which can be removed when you want to clean them.The specialized ventilation design allows air go through the helmet which can help increase the speed and keep cool. LIFETIME MANUFACTURER WARRANTY against defects and a PERFECT FIT GUARANTEE ensures you can order knowing that if it doesnt fit right well replace it immediately or refund your money. Take advantage of this risk-free purchase and invest in your safetyand your looks.