Survival Tip #121
Laser Pointer
This ties into a few other tips, like act strong or improvise. Having a laser sight on your weapons would be helpful, but that might not be something you have on hand. Laser pointers are easy to come by, and their batteries last life times. A red dot on someones chest gives them reason to hesitate.
Justin Kassab 
Consider though that for the most part the batteries are TINY and not readily obtainable.
They do have a long shelf life though. STOCK UP!
I use one embedded in a 3 cell AAA torch. To mount on a shotgun I used a couple of plastic pipe clips, back to back, easy to use, snap on the barrel.
Now the torch sits under the barrel, illuminates the target and the laser “paints” it.
OK, not “accurate” but scary as hell when you are lit up and it allows for flexibility i.e. hand use.