MBU-20/P Oxygen Mask for HGU-55/P Flight Helmet. Mask comes with all parts in photos including intake and exhalation valves, and microphone parts (does not include helmet or CRU-60).Mask and Frame are both size Large Wide. All mask parts pictured included. Check out my other listings for other flight gear. The yellow sticker on the left side of the mask has been removed. I have extra mask parts for the MBU-20/P so if you are looking for something specific please let me know. The item "Gentex Pilot Flight Helmet Oxygen Mask MBU-20/P" is in sale since Thursday, January 9, 2020. This item is in the category "Collectibles\Militaria\Surplus\Hats & Helmets". The seller is "threebikerok" and is located in Oklahoma City, Oklahoma. This item can be shipped worldwide.