434 Combat Readiness Lab

434 Combat Readiness Lab is a location in Kirkland, North America, Earth. It was the testing site of FOTUS-class Mjolnir, a GEN2 Mjonir suit created by 343 Industries.

Trivia
434 uses the same two numbers as 343. This is a nod to the real-world 343 Industries - the current developers and custodians of the Halo franchise. Kirkland, Washington, was the site of 343 Industries' offices (and before them, Bungie) until the studio moved to their current location in Redmond in 2019.

In a post on the Halo Waypoint forums, Catalog mentioned that the 434 Combat Readiness Lab's "Hostile Environment Division" had collaborated with writer Paul T. Scheuring to produce the live-action series Halo: Nightfall.