Armor: Marines Acquire Airborne ATVs
November 29, 2016: In late 2016 the U.S. Marine Corps ordered 144 MRZR4 ATVs (all-terrain vehicles) for delivery in early 2017. This particular ATV was selected because marines had seen SOCOM (Special Operations Command) using it and since some marines are part of SOCOM some of those marines had a chance to try the MRZR4. Another key factor was that the MRZR4 fits in the MV-22 tilt rotor transports the marines (and SOCOM) use.
In 2013 SOCOM began using 1.1 ton MRZR2 and the larger MRZR4 ATVs for their operations in remote areas. SOCOM has ordered over a thousand of these vehicles because users liked them so much that SOCOM had to keep ordering more
https://www.strategypage.com/htmw/htarm/articles/20161129.aspx