Thermoplastic Noryl construction makes the shell very resistant to high heat. The design is curved to deflect sparks & spatter, and seamless to prevent them from catching and burning through. The unique design extends downwards to help block smoke and fumes, and to protect the front of the throat. The shell also curves backwards to protect both sides of the neck. The molded-in glass holder features a 2 x 4 1/4″ aperture for optimal viewing while welding. The Shade 10 welding lens provides clear vision and safe UV/IR protection.