<Back ground>
I bought a 3G Wi-Fi device that is unlocked for any providers so that I would be able to connect to the internet out side of Japan using a local SIM.

<Question>
Now, which one of the following sounds fine?
  1. I bought the device for the international use.
  2. I bought the device for an international use.
  3. I bought the device for international uses.
  4. I bought the device for international use.

I feel OK with the first one, but I am not sure.
Please teach me the logic how I could play with this situation.

Someone taught me that when I use "the" the audience should know what exactly you are talking about.
.. In this case, I am not sure where I am going to go to on the(?) next bussiness trip.


Thank you