Laser-cut ventilation eyelets for enhanced breathability. 6 panels. Strap adjustment by press stud. Head circumference: 58cm... Laser-cut ventilation eyelets for enhanced breathability. 6 panels. Strap adjustment by press stud. Head circumference: 58cm. The visor is made from recycled polythene, which is a tough, light and flexible resin. The recycled polyester used is equivalent to 7/8 bottle of 500 ml.