Petzl - This helmet has a high density expanded polypropylene foam headpiece on the inside and a thermoformed ABS outer shell, providing both lightness and strength.The ergonomic shape provides maximum protection while ensuring a clear field of vision. A single adjustment wheel in the back and an adjustable chinstrap allow for efficient and quick adjustments.Four exterior hooks and a groove in the outer shell are designed to attach and secure a headlamp.Nothing has been left out in this simple, but refined helmet.Technical specifications :Available in 2 sizes:* Size 1diameter: 48-56 cmweight: 300 g* Size 2diameter: 53-61 cmweight: 330 gStandards: CE - UIAA: CE - UIAA