CollectingSnapOn.com

a little rusty but can not find ID...
some has taken the socket trays out of the inside,

gun-metal grey in color..
close to 20" X 7" X 3"

Take a look at the 1935 Catalog KA Supplement p02 - This may be your box.

I think we could tell a little more if we could see the inside of the box and the size. There are several boxes with different partitions inside.

Thanks