151206-N-KR961-006 PACIFIC OCEAN (Dec. 6, 2015) Marines, assigned to 13th Marine Expeditionary Unit (13th MEU), board a CH-53 Sea Stallion on the flight deck of amphibious assault ship USS Boxer (LHD 4). The Boxer Amphibious Ready Group (ARG) is underway off the coast of Southern California completing a certification exercise (CERTEX). CERTEX is the final evaluation of the 13th MEU and Boxer ARG prior to deployment and is intended to certify their readiness to conduct integrated missions across the full spectrum of military operations. (U.S. Navy photo by Mass Communication Specialist 2nd Class Debra Daco/Released)