Prone (IMAGE) U.S. Army Research Laboratory Caption Army Sgt. Michael Zamora assumes a prone fighting position using a prototype Third Arm exoskeleton device during testing at Aberdeen Proving Ground, Maryland, March 14, 2018. Credit (US Army photo by Conrad Johnson) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.