What type of lock is this ?

[LocksmithArmy]

the army uses somthing like this when we ship our conexes over seas.

the armys are a little different and are ment to be cut off. i dont know about these here though. i will try and get some from my supply and take pictures for you all.

I left my camera in the car seat back in the states while i was home so you will have to wait on it to come in the mail. sorry for the delay

[raimundo]

Its a seal, it has an aluminum cap and it can be removed with a pen barrel if I remember the one time way back in the '80s when I had the opportunity to look at one of these.
The original poster says he has a lot of custom made tools in the trucks, I don't know if he wants to buy seals and break and replace them as necessary, masterlock has laminated padlock type seals,
but since the OP fabricates his stuff, I would think that he could make a seal or lock that would fit his particular needs.
how hard could it be?