i have no clue what this is but i hope you guy's do.......
5/8 male and 7/8 female square, 7/16 hole bored though it. the only mark is a 7. it was in a toolbox i bought but it may not be a tool?
(http://i220.photobucket.com/albums/dd154/matco01/2012111595072907_zps7abe3398.jpg)
Looks like a socket made for dual wheels on old trucks. The inner dual was held on by a square head bolt on a few brands. The outer wheel by a large nut.
Similar were used on mains water valves - different comanies had different sized keys, and sometimes an adaptor was required to operate a valve with a standard key....
Can't help, but that's sure a dramatic shot!