The custom blast-resistant roller windows feature the Triple “H” Combination of the “H” seal, the “H” Frame, and the “H” Wedge for maximum sealing efficiency. This extremely rigid shock-resistant “H” Frame is constructed of 1/16″ stainless steel. Special silicone rubber U-seals around the glasses and between the mounting provide dual protection against high temperatures while maintaining the tightly sealed air space. Metal wedges exert a positive pressure on the “H” Frame to the Outer Frame, producing a safe air-tight seal against noise, dust, and fumes.