Damn, you're right. I just looked it up. Never seen one like that.Battery terminal cleaner. That part sticking out goes on the inside of the cable terminal and the other side will slide out and go over the terminals on the battery
That's an oldie. Used to have the same one
There's a really thin gauge wire wound around the springs that scrubs off a small amount of the lead on the terminals when you spin it back & forth.BLUE-POINT TOOLS BATTERY Terminal Cleaner Brush Tool - BTC-6 - Made in USA - $29.99. FOR SALE! Blue-Point Tools Battery Terminal Cleaner Brush Tool BTC-6 Made in USA 143947924471picclick.com
Looks like a beam clamp to use for rigging or an anchor point.