Aerox's High Altitude Diluter Demand Mask is approved for use up to 40,000 feet. per TSO C89A and TSO C78A. Includes our Comfort Fit Headgear, Silicone face piece for maximum comfort and carbon fiber shell. Comes with electret microphone. Select the mask size, hose length, and oxygen connection below. Combine with 5110-100 Aerox Smoke Goggles and portable bottle for a standalone emergency kit!