An update to the aging M3 vest, M4X armor provides better protection against high-velocity impacts than its predecessor without sacrificing mobility. Instead of a basic vest and infantry 'bucket' helmet, the M4X incorporates full-body protection with armored sleeves, thick gloves, and a full-face helmet complete with a light ballistics-resistant visor. While the M4X is superior in all aspects to the M3, the armor is still undergoing field testing with several Marine combat units before being issued to the entire US Colonial Marine Corps.