They were based upon during the great technological exchange between the nations of Urauslain and China. Sadly, however, America procrasinated in the design and developed of their version of the battlesuit technology and science, while, the other nations were working overtime and overbudget to develop their own versions of the battlesuit technology and science.
Ukraine Zombie Outbreak.
During the very first days of the near-global outbreak, the Armed Forces of America had just, already, mass productions of their own versions of the Urauslain's Lenoid Battlesuit Armor to the point that the American soldiers we're getting useful to battlesuit armor, when, it just began to become near-global levels.
Sadly, however, the American version of the battlesuit armor was neither more progressed nor much advanced as the other nations' versions of the battlesuit armor technology and science. It was because of this that infection spread more, rapidly, across the United States of America.