Region testing

[DrrnHarr]

Hello,

I'm not sure if this is the correct forum but I wanted to know how to indicate that a DVD works in a specific region.

I own a Region 1 player (being here in the United States).

I own the DVD for "The Fourth Protocol" listed here:
https://www.blu-ray.com/dvd/The-Four...8483/#Overview

Amazon lists the movie as All Regions which I do not know if its accurate. Blu-ray.com lists the regions as untested.

However the DVD does play on my Region 1 player.

Thank you.