WhatZit?

[Mark Rozak]

What is it? Looks like a bracket for mounting boxes. It has one strap with lever lock. The center hole almost allows the plastic 5 Gal fuel can to slide in. Four mounting holes, on the aluminum frame bracket.

Red arrow shows closeup of special side slot

[dilvoy]

OK I'll take a guess. Is it a Polish Army protective helmet with chin strap?

[emmado22]

It's something for cargo aircraft use with that round track system on the bottom of it.

[Mark Rozak]

Yeah, kinda figured with the track lock. Somebody said it's for water and fuel cans. Not for the current plastic ones. The strap is like a paratroopers.