Polyethylene construction, with internal breathable and hypoallergenic lining (polyamide). Consists of two ergonomic self-grip valves with Velcro. Features a tracheotomy aperture. Height adjustment system with a choice of six positions (for extension and hyper-extension of the neck), as well as a mechanism for adjustment of the angle of the chin rest for proper fit. Features ventilation holes. Radioluscent.