I was driving on country road ,lots of curves, headed down hill to a river valley.I slowed for a sharp curve and spotted a loading ramp off to the side of the road I stopped and put it in my truck, further down the hill I spotted the mate,stopped and picked it up.Twenty miles from the nearest town on a lightly travelled secondary road.I didn't see a trailer anywhere along the road for the next while.No identification on the ramps.
The ramps were well made, constructed using expanded metal and angle iron with good welds. My guess is someone had put them on a flat deck trailer,probably empty, hadn't strapped them down and bouncing along the ramps slipped off on the curves.
I've used them for the last 25 years.