FEATURES of the Petzl Vertex Vent Helmet Shock absorption achieved through deformation of the outer shell Strong chinstrap (more than 50 daN) limits the risk of losing the helmet during a fall Six-point textile suspension conforms perfectly to the shape of the head CenterFit adjustment system adjusts the headband and keeps the helmet centered on the head Vent holes with sliding shutters allow the ventilation to be adjusted as needed, while wearing the helmet Comes with two sizes of headband foam