It can be put under pressure. I have picked up that the devices were chemical bombs in 2 liter soda bottles.
They make a lot of noise and are hell on mailboxes.
"I have picked up that the devices were chemical bombs in 2 liter soda bottles."
In the OU case they confiscated 13 plastic bottles from the trunk of Hinrichs car. A terrorism expert on Fox News the other day said that bombs usually made with these types of bottles are not that innocent (your reference to loud noise and mailboxes). The expert (don't know who exactly it was) said that if they are exploded say inside a bus it could easily kill 100 to 150 people...
I've yet to read through the rest of these posts, but let's hope it was not these types of devices that was found. Hopefully it is a prank of some sort...