Ok, I have mine and here is my first review.
They are a soft plastic similar to rubber. They have a small magnet that would not work for putting on a truck or trailer and towing anywhere is it will fall off (more on that later).
The hook on the back comes out perpendicular to the back, that means you have to hook on a vertical post, not hang it from a wire or line.
Seems well built and one of mine had bad batteries in it that I can assume is from someone playing with it and leaving it on. The other three were good.
Here are the pics and you can get an idea from the card how big they are.
They have 6 modes:
All off
3 LEDs in the center on
12 LEDs on edge on and off like a car on a track in a circular motion
12 LEDs on edge on and off like a car on a track in a circular motion but strobing (my personal favorite)
12 LEDs on edge on and off together
12 LEDs on edge all on
3 AAA batteries
Now to the downside, they are not mower proof. I had 4 lights in the morning and by 2 in the afternoon I had two left. I had put all four on the roll bar of the big mower to take them to the barn and promptly forgot they were on there. The first brush I hit knocked all four off and I hit 2 of them with the blades. I only found enough pieces to make 1.5 of the destroyed pair. Who knows where the rest went but bright neon orange against green should have made it easy to see. No, not my blind spot either as I found a nice fat dark green striped Garter Snake laying in the grass.
End result
I like them and will probably order replacements.