What are tubes behind cab?

[Awesomeness]

I was watching the video below and noticed these tubes attached to the rear of the cab of an MTV. What are they?



Video:
https://www.youtube.com/watch?v=LPFP0sTk8a8

 

[wheelspinner]

Being that it's a wrecker I'll bet early beacon mounts.

 

[319cssb]

This is what the beacon mounts on a m1089 look like.

Some call the m1089 a rocket launcher, (my idiotic brother in law) and then some ask what those tubes behind the cab are.

 

[Third From Texas]

Look to be beacon mounts to me. With the lenses removed and just the raw strobe in the video).