Pelican cases are both U.S. Mil-Spec and STANAG. (NATO standard testing agreement.)

They have to be dropped from a height of one meter onto solid concrete and made to land on all six sides. They are frozen at -20C for up to seven days. They get baked at 50 C for 48 hours. They are shaken on a vibration machine for up to six hours. Then they perform the testing procedures on 24 identical samples and they have to survive all these tests with only minor, cosmetic damage.

That's just for the standard Pelican case. The Pelican "Storm" cases have to survive all those tests AND they have to survive being submerged in 1 meter of water for a given period of time without any leakage.

Long story short: Don't screw around. Just get the Pelican.