Flight helmet HGU-68/P with a free MBU-20P oxygen mask

This is a Gentex HGU-68/P flight helmet. It was imported from the United States. After arrival, I opened the top lid of the box, unzipped the helmet bag, looked at it from above, closed the zipper, closed the top lid, and stored it. I am the type of person who is satisfied just by purchasing. As a gift, I will include the MBU-20/P, also from Gentex. I took it out of the bag for the first time to take photos for this listing. The helmet color is matte brown. The size is Medium. US military aviation helmets are mainly available in M, L, and XL sizes, with fine adjustments made using the inner liner. M is approximately 59cm in head circumference, L is 60-61cm, and XL is 62cm or more. Actual US military sizes are generally indicated in inches and are slightly larger than Japanese sizes.

Main size indications and approximate measurements (varies by helmet type):
M (Medium): US Size ~ (approx. 58-59cm)
L (Large): US Size ~ (approx. 60-61cm)
XL (Extra Large): US Size ~ (approx. 62cm or more)

The helmet bag and clear visor (for night flight) will also be included. How about it for fighter jet enthusiasts? By the way, there is currently only one item listed on Sekaimon. The final total payment was 499,413 yen, and that was without the MBU-20/P mask. Due to recent issues with returns, etc., as reported in the news, I would like to decline any returns or complaints. For your reference, the 9th photo shows a current Japan Air Self-Defense Force helmet. Although the color is different, don't you think they look similar? That's why I researched it and thought it was a similar helmet when I purchased it. Thank you.