A few years ago auto zone had a three pack of safety flare led "pucks" for $15. After checking a set out once home, I ended buying another 3 set I think it was due to having 3 vehicles (4 "pucks" in each). We now only have two vehicles, but luckily I have never had to use them while towing. Only time I have used them was when on wife guard (work for a utility co.) due to numerous down power lines. Was told by a few people that the three puck lights were pretty easy to see at night.....
I have one if those collapsible led cones also I now carry, given to us at work for our safety kick off this past winter.