What is this item?
 

Certainly military..

a flat tank, presumably for rad fluid (??)
they are thin, about 1-inch , and roughly 6 in by 10 in
A brass connector on one end to accept about a half inch threaded connnector

while out the bottom (or side?) a hose with a clamp would likely be fitted..

Interesting in that there are no pre-drilled mounting holes, but have flanges on three sides.. would it be slid into place??

any ideas as to application?

No-one? they are absolutely from mil vehicles.... so clues???

They are certainly military, but if after a couple hundred views, and no ideas...well I cant think of any use for them, so so perhaps I may as well bin them.

no idea mate, any numbers on them anywhere? what does the other side look like?

R

just flat