U.S. Marines with India company, 3rd Battalion, 2nd Marines, conduct training at the Infantry Immersion Trainer site on Marine Corps Base Camp Lejeune, North Carolina, April 4, 2023. The IIT is designed to provide Marines with a realistic combat environment using sound, smell, atmospherics and role-players to increase combat efficiency. - U.S. Marines with India company, 3rd Battalion, 2nd Marines, conduct training at the Infantry Immersion Trainer site on Marine Corps Base Camp Lejeune, North Carolina, April 4, 2023. The IIT is designed to provide Marines with a realistic combat environment using sound, smell, atmospherics and role-players to increase combat efficiency.