Petzl Vertex Vent Climbing Helmet Blue. The adjustable-strength chinstrap makes it ideal for both work at height and on the ground. It has ventilation holes with sliding shutters to allow airflow through the helmet. With its potential for integration of a Petzl headlamp hearing protection and multiple accessories it is an entirely modular helmet thus responding to the specific additional needs of professionals. Specifications for Petzl Vertex Vent Climbing Helmet: Manufacturer: Petzl Size: One Size Head Circumference: 20.9 - 24.8 in Gender: Unisex Fabric/Material: ABS acrylonitrile butadiene styrene nylon polycarbonate high-strength polyester polyethylene Weight: 490 g Features of Petzl Vertex Vent Climbing Helmet Very comfortable: six-point textile suspension conforms perfectly to the shape of the head; CENTERFIT feature allows perfect centering of the helmet on the head thanks to its two side adjustment wheels; FLIPa nd FIT system allows the headband to be positioned in a low position guaranteeing that the helmet fits securely on the head. The system folds into the shell for easy storage and transportation; comes with interchangeable standard comfort foam Protection designed for work at height and on the ground: DUAL chinstrap allows the worker to adjust chinstrap strength in order to adapt the helmet to different environments: work at height (EN 12492) or on the ground (EN 397). The clip has two positions corresponding to these two uses: high strength limiting the risk of losing the helmet during a fall and low strength limiting the risk of strangulation if the helmet is snagged while the user is on the ground; shock absorption achieved through deformation of the outer shell; vent holes with sliding shutters allow the ventilation to be adjusted as needed while wearing the helmet Package Contents: Petzl Vertex Vent Climbing Helmet Petzl A010CA05: Vertex Vent Climbing Helmet Blue