Very light metal object

[joesdigs]

Hey guys. Wondering if anyone knows what this piece is? It's very light. But strong.. Has a cross on one side well the shape of a cross and is sort of dimpled on the other side. Thanks guys

 

[darthoblio]

It looks to me like a cap or plug for a rectangular metal tube, like a post or something. This would be the kind of thing that's pressed into place, probably cast aluminum. If so, I'd guess it's not too old.