PETZL - Vertex Best CSA Helmet Six-point webbing suspension system conforms to the shape of the head for improved comfort. Shock absorption achieved through deformation of the outer shell. CenterFit adjustment system ensures centering and optimal stability of the helmet on the head Side slots for mounting hearing protection and inserts for accepting a VIZIR face shield Chin strap designed to limit risk of losing helmet during a fall (strength greater than 50 daN) The helmet's unventilated shell protects against electrical hazards and molten metal splash