What kind of gift would you buy for a 16-year-old who's into military stuff?

My nephew is turning 16 soon, and we're really close. He comes over to my house all the time, and I've made it a tradition to get him a birthday gift every year.

The problem is, it's getting harder and harder to figure out what teenagers are actually into these days. 😅

He's really interested in military topics—guns, fighter jets, tanks, military vehicles, that kind of stuff. He's always watching videos or reading about them.

I'd love to get him something he'll genuinely enjoy, but I'm running out of ideas. I'm open to anything, whether it's collectibles, model kits, books, gear, experiences, or something I probably haven't even thought of.

What would you recommend for a 16-year-old with these interests?